Fantasy Breakdown: Seattle Mariners for 2021

A preview of the Seattle Mariners' team for 2021.

As we prepare for the season ahead, the Pitcher List staff will be creating profiles for every fantasy-relevant player for 2021. Players will be broken up by team and role through starting pitchers, bullpen, lineup, and prospects. You can access every article as it comes out in our Player Profiles 2021 hub here.


At A Glance


While the 2020 season had the Mariners finishing with a middling record, it also gave them the opportunity to see more out of their youngsters, and they were rewarded with glimpses of hope for many players and potential breakouts for others.

On the offensive side, the Mariners saw Kyle Seager continue his revitalization, with him being characteristically reliable — he played in every single game — but also posting a 118 wRC+ over those 60 games. They had some strong offensive seasons from players that were more expected — Kyle Lewis is perhaps the most prominent example — but we also saw players like Dylan MooreAustin Nola, and Ty France flash some promise. Evan White, Shed Long, and Jake Fraley had disappointing seasons, but in just 60 games with an abnormal schedule, it’s difficult to take their seasons at face value.

For the rotation, much is the same. Marco GonzalesYusei Kikuchi, and Justus Sheffield will look to anchor the rotation, with Justin Dunn and Nick Margevicius making up other returners. To round out the six-man rotation (for now), the Mariners added KBO breakout Chris Flexen to continue his dominance and further bolster the rotation.

Perhaps the most improved section of the roster, though, is the Mariners’ bullpen. Of course, Jerry Dipoto stated that this was his intention, but they’ve gone from the worst bullpen by fWAR in 2020 to projected to be 19th in fWAR in 2021 by FanGraphs’ Depth Charts. They’ve done this by overhauling nearly the entire bullpen. Kendall Graveman will pitch exclusively out of the bullpen, while Anthony MisiewiczCasey Sadler, and Erik Swanson are the only other returners. Rafael Montero was acquired via trade from the Texas Rangers while Keynan Middleton was signed from free agency and Will Vest was drafted in the Rule 5 Draft. It wouldn’t be surprising for this group to be significantly better than their projection, and they’re not done adding yet.




Projected Lineup




J.P. Crawford (Shortstop)

2020: 33 R, 2 HR, 24 RBI, 6 SB, .255/.336/.338 | SS #17

2021 ADP: 421.12 (SS #37)


In 2019, J.P. Crawford made an adjustment akin to Jean Segura that precipitated a spike in power. The breakout, I thought, was legitimate, and so I wrote it up! Shortly thereafter, the thump in Crawford’s bat went by the wayside, and it’s yet to come back.

In terms of batted ball data, Crawford is about as underwhelming as it gets. He ranks in the ninth percentile in exit velocity, and in the 15th percentile in hard-hit percentage. Still, the Mariners believe internally that more power is to come — he’s just 26 years old — and he still makes good swing decisions and good contact.

For now, he’s a mainstay in the Mariners’ lineup because of his glove, and he’s going to spend a lot of games atop the lineup, too. I still think there’s some power hiding somewhere in there, but regardless, he’s going to hit double digits in home runs and stolen bases, and his batting average shouldn’t sink you.


Dylan Moore (Second Base)

2020: 26 R, 8 HR, 17 RBI, 12 SB, .255/.358/.496 | 2B (Unranked)

2021 ADP: 110.78 (2B #11)


In 2019, there was a game where Dylan Moore had three errors in one inning. After that game, I didn’t see any point in the Mariners keeping him on the roster. He couldn’t hit, he couldn’t run, and he apparently couldn’t field, either. Then, over the offseason, Moore made some adjustments to his swing and his bat became one of the most potent in the Mariners’ lineup.

It seems legitimate too! His strikeout percentage is down, while his max exit velocity, dynamic hard-hit rate, and barrel percentage are up. He’s tightened up his sd(LA) too, which means that he’s hitting the ball at much more consistent angles. Small sample notwithstanding, he looks like a superior hitter to Kyle Lewis, as is.

Even if Seattle adds a second baseman (it seems like they won’t), Moore will get plenty of plate appearances in left field and roving around the infield to spell starters. More likely, they’ll add an outfielder, and so Moore looks set to contribute 20+ home runs with 25 or so stolen bases. THE BAT X and ATC like him quite a bit, which speaks to the legitimacy of his potential breakout. There isn’t a player that I’m targeting more than Moore given his potential production versus draft position.


Kyle Seager (Third Base)

2020: 35 R, 9 HR, 40 RBI, 5 SB, .241/.355/.433 | 3B #4

2021 ADP: 262.62 (3B #30)


A little over a year ago, I wrote that Kyle Seager was back — but with a caveat. That is, Seager was hitting the ball as well as he’d been since 2016, but he was also propping his production up by pulling fly balls in the air to his pull-side. Of course, that’s an approach that works for many. We needn’t look outside of the AL West to see that Alex Bregman has leaned on this approach that would expose him outside of Minute Maid Park.

He started 2020 looking like a whole new player. He was being patient, and it looked like he had an entirely new batted ball profile. After looking like Michael Brantley for a month or so, Seager reverted back to his old profile and id was Seager does: he played every game of the season and provided steady production.

THE BAT X and ATC are believers. They think his power is back to 2016/2017 levels, and forecast 29 and 24 home runs, respectively, with a few stolen bases for good measure. His batting average isn’t going to win you leagues, but in the unlikely scenario in which he moves towards his early 2020 ways (i.e., contact- and groundball-heavy), he could see a large jump in batting average.



Ty France (Designated Hitter)

2020: 19 R, 4 HR, 23 RBI, 0 SB, .305/.368/.468 | 2B #29

2021 ADP: 305.46 (2B #29)


By outcomes, France was about as good as you could expect during his 43-game sample in 2020. His .390 BABIP hints that he was probably playing over his head and his Statcast data supports this! His .356 wOBA just inches out his .346 xwOBA, so there’s not much regression to be expected there, but there are worrying aspects to his profile.

Namely, if you saw his Statcast sliders, you might think he was J.P. Crawford. He ranks in the eighth percentile in exit velocity, in the 11th percentile in hard-hit percentage, and in the 56th percentile in barrel percentage. Generally speaking, that speaks to impending regression — but that may not be the case.

By launch angle tightness, France ranks among the best in MLB. I’ll admit, I don’t recall the exact year-to-year reliability of launch angle tightness, but I wouldn’t bank on France repeating it. If he can, a strong sweet spot percentage can make up for the lack of thump in his bat, but several different websites seem to think France will be able to tap into a little more power. (After all, it’s only been 356 plate appearances.)


Evan White (First Base)

2020: 19 R, 8 HR, 26 RBI, 1 SB, .176/.252/.346 | 1B #48

2021 ADP: 390.52 (1B #40)


After just 400 plate appearances in Double-A and 18 in Triple-A, the Mariners tossed Evan White into the thick of things, giving him the starting job at first base after signing him to an extension. He returned mixed results, looking strong at times, but overmatched most often. His overall .176/.252/.346 was horrid, but perhaps most troubling is his 41.6% strikeout percentage.

Almost everything looks really bad, but it’s easy to remember that White essentially jumped from Double-A into a starting job at first base at the age of 24. He’s never showed significant swing and miss issues at the college or minor league level, so I’m more likely to think that this is just a function of adjusting to major league baseball.

On the bright side, THE BAT X thinks he’ll be a league-average bat by wRC+. That makes sense! White swung and missed a lot, but when he did make contact, he tore the cover off the ball. He popped a 112.8 max exit velocity, and he grades out extremely well by exit velocity (87th percentile), hard-hit percentage (95th percentile), and barrel percentage (90th percentile). The Mariners invested a lot of money in him, and he has arguably an 80-grade glove at first base, so he’ll get plenty of looks in 2021.


Tom Murphy (Catcher)

2020: N/A

2021 ADP: 328.08 (C #21)


After finally — finally! — getting a look as a starting catcher, Murphy came through in a big way, posting a .273/.324/.535 triple slash with 18 home runs and two stolen bases over 76 games.

Despite Murphy’s career numbers now up to a relatively full season (i.e., 157 games and 491 plate appearances), the projection systems are in agreement that Murphy is more of a .215/.275/.415 hitter, as opposed to the .250/.301/.493 he’s been over his career.

On the plus side, Murphy has a ton of power to his game. On the, uh, not-plus side, that also comes with a ton of swing and miss, and he and Luis Torrens are said to essentially share time at catcher. Age isn’t on his side, and his approach (i.e., pulled fly balls) could be easily exposed. With that said, the disparity between his expected and actual performance he showed in 2019 (.355 wOBA/.303 xwOBA) may not be as significant as it appears.

With Luis Torrens on the roster — who Seattle thinks highly of — and Cal Raleigh on the way, Murphy doesn’t have much margin for error.




Kyle Lewis (Center Field)

2020: 37 R, 11 HR, 28 RBI, 5 SB, .262/.364/.437 | OF #26

2021 ADP: 124.04 (OF #32)


Speaking of Kyle Lewis, he’s being drafted right after Dylan Moore! Lewis got off to a torrid (albeit unsustainable) start and sustained it until September, where his plate skills took a nose dive — OPS’ing .550 and striking out 37.1% of the time. THE BAT X and ATC have Lewis projected for similar numbers to Moore, but with about 20 fewer stolen bases.

The strikeouts are a legitimate part of his game, but he seems more like a 25-30% strikeout guy as opposed to the high-30% strikeout numbers he’s flashed at times. That’s always going to limit his batting average, but Lewis looks like a legitimate major league hitter more than ever.

It’s going to be interesting to watch how Lewis adjusts. He spent a lot of 2020 taking what was given to him and doing his best with it. Oftentimes, that meant taking the ball the other way or up the middle. To maximize his skillset, though, Lewis is going to need to start hitting the ball in the air to his pull-side — something we know he’s capable of but has yet to do at the major league level.


Mitch Haniger (Right Field)

2020: DNP

2021 ADP: 286.39 (OF #78)


Mitch Haniger has had a helluva year or two. After struggling in early 2019, Haniger ruptured his testicle on a foul ball, which led to surgery and other complications as a result of the injury. He ended up tearing a muscle in his groin area (which occurred during rehab) and had a herniated disc in his back (which occurred as a result of the torn muscle in his groin area. Just awful, awful luck.

Now on the wrong side of 30, Haniger has posted several videos of unconventional workouts that he’s been doing to strengthen his core and stay healthy. General manager Jerry Dipoto has said that he’s “full go” for spring training and that he looks “terrific”.

Surprisingly, projection systems all think very highly of him, with THE BAT X and ATC being the most optimistic (which is a great sign). Despite numbers that are relatively similar to Kyle Lewis‘, Haniger is set to go over 160 picks later. The injury concerns are legitimate, but there’s little reason to think that Haniger won’t return to form if he’s healthy.


Sam Haggerty (Left Field)

2020: 7 R, 1 HR, 6 RBI, 4 SB, .260/.315/.400 | OF #134

2021 ADP: 686.82 (OF #149)


Despite a strong hard-hit percentage and sweet spot percentage, Sam Haggerty wasn’t able to join the two together for a strong barrel percentage, posting just one barrel out of 34 batted ball events. The end result was a .260/.315/.400 triple slash, and .299 xwOBA and .306 wOBA.

None of the projection systems at FanGraphs think very highly of him, and there’s a fair chance he gets replaced before the outset of the 2021 season, but if Haggerty is able to put it together even a little, there’s a ton of upside for some power and a lot of steals.


Watch List Considerations


Aside from Torrens, Shed Long Jr. is perhaps the only player that will be relevant that’s on the major league roster. Long Jr. put the ball on the ground far too much last year, but he’s not lacking upside. It’s highly likely that the Mariners make an addition via free agency.

In the minor leagues, the Mariners have several outfield options in Taylor Trammell, Jake Fraley, and Jarred Kelenic. Fraley looks like he may be on his way out, but Trammell and Kelenic are both extremely interesting options that will likely both accrue major league time in 2021. Sam Travis could be someone to keep an eye on, but probably not.


Starting Pitchers


Marco Gonzales (Locked In Starter)

2020: 7-2, 69.2 IP, 64 K, 3.10 ERA, 0.95  WHIP | SP #9

2021 ADP: 159.97 (P #58)

Repertoire: 45.2% Sinker, 24.4% Cutter, 16.1% Curveball, 14.3% Changeup


Marco Gonzales is shaping up to be one of those players that puts his head down and posts consistent, productive numbers despite underwhelming swing and miss numbers. Despite his swinging-strike percentage being one of his lowest season numbers since 2017, he posted easily his highest called strike percentage, leading to his highest CSW at 30.8%.

Gonzales’ CSW is propped up by his sinker by usage (45.2%) as well as its 34.0%, as well as his curveball’s 37.6%. He could stand to throw the curveball more, and given its 45.3% chase percentage in 2020, he could stand to throw it out of the zone more as well.

I wrote up Marco Gonzales‘ 2020 over at Lookout Landing, where I said that his release point has been tightening and, as a result, his command has been as precise as ever. (The percentage of his pitches that ended up in Baseball Savant’s “shadow zone” ranks in the 99th percentile in baseball.)

Notably, Gonzales walked fewer hitters than ever, and he has also optimized his ability to get to two-strike counts. The only hangup is he’s much better at earning strikes in non-two-strike counts, but I’ll note that his two-strike CSW ranks in the 47th percentile — so he’s about average in that sense.

If you like Kyle Hendricks, you should like Gonzales.


Yusei Kikuchi (Locked In Starter)

2020: 2-4, 47.0 IP, 47 K, 5.17 ERA, 1.30 WHIP | SP #139

2021 ADP: 343.43 (P #129)

Repertoire: 40.0% Cutter, 37.7% 4-Seam Fastball, 16.0% Slider, 6.3% Changeup


In 2019, Yusei Kikuchi was extremely underwhelming. In fact, he was about as bad as you could have expected to be. By outcomes, he wasn’t much better in 2020 — his ERA only increased from 5.46 to 5.17 — but his peripherals were significantly better, as was his overall process.

The cause? Well, many different things! He overhauled his repertoire and cleaned up his mechanics over the offseason and looked like a whole different pitcher. I wrote it up at Lookout Landing, but the crux is that he added ride and velocity to his fastball, turned his slider into a 92 mph cutter, and turned his curveball into what is essentially his slider from 2019.

Kikuchi’s looks like a legitimate whiff pitch, and his cutter looks like a potent contact suppressor. The issues, as I see it, are that Kikuchi has struggled mightily with fastball command (which has resulted in a lower called strike percentage than is ideal), and he’s not throwing his slider as much as he should. (In my opinion, his slider may be his best pitch.)

Cleaning up his fastball command alone has the potential to turn him into an ace-like pitcher. If he throws the slider, too? He could be lights out.

(Also, a couple of pertinent notes from Alex Chamberlain here and here.)


Justus Sheffield (Locked In Starter)

2020: 4-3, 55.1 IP, 48 K, 3.58 ERA, 1.30 WHIP | SP #70

2021 ADP: 285.62 (P #106)

Repertoire: 47.4% Sinker, 33.5% Slider, 18.4% Changeup


About a year ago, I — you guessed it! — wrote about Justus Sheffield’s spring training changes. Before the 2020 season, Sheffield scrapped his four-seam fastball in favor of a sinker. That was a judicious decision, to an extent. Sheffield threw a bowling ball four-seamer in 2019 that sunk more than a four-seamer but didn’t get the arm-side run of a sinker. Now he’s throwing a sinker that a little more sink than your typical sinker.

It looks like his two fastballs are equal contact suppressors, but he did a better job of throwing strikes with his sinker. The issue became that he stopped throwing his slider for swinging-strikes, which is perhaps because the disparity in vertical movement between his primary fastball (i.e., his sinker) and his slider closed. He also, on average, threw his slider higher vertically in the zone.

In 2019, he was a pitcher with a bad fastball and plus slider (given its 23.8% swinging-strike percentage). In 2020, he was a pitcher with a less-bad fastball and a slider that had its swinging-strike percentage drop to 13.2%. He completely leaned into being a pitch-to-contact pitcher with mixed results. On one hand, he’s relying more heavily on his defense, but also, his K-BB% improved slightly from 11.3% to 12.1%, and his xFIP dropped from 4.68 to a more manageable 4.27.

I still have significant doubts about Sheffield, but he showed that he can be serviceable in 2020.


Chris Flexen (Likely Starter)

2020: N/A

2021 ADP: 666.19 (P #272)

Repertoire: 61.8% 4-Seam Fastball, 16.9% Slider, 12.5% Curveball, 8.8% Changeup


After posting one of the Korean Baseball Organization’s best pitcher seasons ever, the Mariners inked Chris Flexen to a two-year deal to give him another shot as a starting pitcher. Hear me out…I wrote about Flexen for Lookout Landing, and I came away feeling good about him as a starting pitcher.

Flexen features an underrated fastball that he pairs with a slider, curveball, and changeup. He threw them all for strikes in the KBO but, save for making some tweaks, his fastball and curveball seem to be the pitches that are going to pop in MLB.

To play devil’s advocate, the biggest change for Flexen from 2019 to 2020 wasn’t something that he did himself. What changed the most is that he went from being mediocre by velocity in MLB to being the KBO’s second-hardest throwing starter. He did increase his curveball usage, but it wasn’t enough to move the needle this much.

Flexen isn’t going to be able to lean on his fastball as much as he did in the KBO — at least, I would think — and I would like to see him double his curveball usage at the very least. There’s a strong chance that Flexen is a good starter in 2021, but there also remains the chance that he’s quite mediocre, too.


Justin Dunn (Fringe Starter)

2020: 0-0, 0.0 IP, 0 K, N/A ERA, N/A WHIP | SP Rank N/A

2021 ADP: 252.76 (P #95)

Repertoire: N/A


On one hand, Justin Dunn made it through an entire year without any hiccups. On the other hand, he wasn’t very good. Over ten starts, Dunn posted a 6.23 xFIP that included a 3.5% K-BB% and 1.97 HR/9.

That’s in part because he was a rookie in his first full (albeit shortened) season, but given the pitcher that he is now, I wouldn’t expect much better going in 2021. I wrote at Lookout Landing that he was in need of a tweak (or three), and that’s because his pitches don’t separate from each other. His changeup gets zero separation from his fastball — it’s like a sinker if it sat 87-88 mph — and his curveball and slider are too similar too.

While the Mariners should be a team that is best able to help Dunn re-shape his pitches, it’s not something I’m counting on. As is, he looks like a player that is destined for the bullpen, and even if he makes some tweaks to his pitches, he still struggles with his fastball command.


Nick Margevicius (Fringe Starter)

2020: 2-3, 41.1 IP, 36 K, 4.57 ERA, 1.26 WHIP | SP Rank #28

2021 ADP: 726.61 (P #329)

Repertoire: N/A


Despite being kind of underwhelming on the whole, Nick Margevicius is able to piece together a collection of pitches to be a decent starting pitcher. He leans heavily on a fastball that, despite well below-average velocity, features good ride and is a pitch that he can throw very a lot of strikes at times.

The hangup for Margevicius is that he doesn’t have any secondaries to pair with his fastball. While his curveball gets an insane amount of drop, it’s more of a get-me-over offering because it’s thrown just 70 mph. It draws very few whiffs, but it also draws so many called strikes that it boasted a 30.8% CSW in 2020. His slider gets put into play too often, and he doesn’t throw his changeup very often.

Margevicius is a good candidate for tweaking his secondaries but, again, I wouldn’t bank on it. If he does, he has a good fastball and good command that he could pair with a stronger curveball or slider. If he doesn’t, he should continue to put up league-average numbers without a strong grasp on a secure role.


Ljay Newsome (Fringe Starter)

2020: 0-1, 15.2 IP, 9 K, 5.17 ERA, 1.34 WHIP | SP #207

2021 ADP: 748.14 (P #902)

Repertoire: 49.4% 4-Seam Fastball, 26.7% Curveball, 23.9% Changeup


Despite not having the build or tools that are typical of a minor league pitcher that overwhelms his opponents, Ljay Newsome has long been a peripheral prospect darling of Alex Chamberlain. After being somewhat underwhelming in Single-A and High-A in 2017 and 2018, Newsome popped off in 2019, featuring strikeout numbers like he never had before. This came after Newsome’s participation in the Mariners’ Gas Camp.

After attending Gas Camp, Newsome went from sitting 88 mph to about 91 mph, which remained steady upon his major league debut. At Lookout Landing, I tabbed Newsome as a developmental success, given that he’s one of few Mariners to rise through the system and look like contributors at the major league level.

To date, Newsome has used his curveball as more of a get-me-over pitch rather than something he uses to get hitters to chase. He should look to change that if he wants to be a starter. As for his changeup, it looks like it benefits from seam-shifted wake, and despite its firmness, it also gets a surprising amount of vertical separation from his fastball — aside from the forces of gravity, his changeup doesn’t move vertically.

Newsome has long been an interesting pitcher to me. He’s more likely to end up in a bullpen role than a starter role, but he’ll get some looks as a starter this year. Hopefully, he’s got a new secondary or two in his future.


Watch List Considerations


It may not feel overwhelming, but the Mariners have a lot of depth in their starting rotation. Given that they’ll be going with a six-man rotation, it’s even clearer that Logan Gilbert will have a path to major league innings in 2021, and they’re probably not done adding.


Relief Pitchers


Bullpen Roles


Rafael Montero (Closer)

2020: 8 SV, 0 HLD, 17.2 IP, 19 K, 4.08 ERA, 1.02 WHIP | RP #56

2021 ADP: 193.99 (P #191)


Barring an unexpected move, Rafael Montero is set to receive the vast majority of closing duties for the Mariners. Despite a solid 22.7% K-BB%, Montero has struggled with the gopher ball (1.35 HR/9) and has posted a .320 and .317 xwOBA in 2019 and 2020, respectively.

The home run issues are less of a feature of his fly-ball profile and more to do with Montero getting hit really, really hard. Since 2019, Montero has yielded a 14.5% barrel percentage, which is probably legitimate given that it’s over two times the league-average barrel percentage and was over 117 batted ball events.

The hard contact is disproportionately a fastball issue. It has a 9.3% blast percentage and 25.6% barrel percentage. Those numbers will surely fall over time, but the issue itself seems legitimate. Montero lost over an inch of fastball ride despite seeing an uptick in velocity, and so there may be some mechanical tweaks the Mariners are hoping to rectify. Pitch mix changes and added pitches are always more likely when players change teams, too.


Kendall Graveman (Next In Line)

2020: 0 SV, 5 HLD, 18.2 IP, 15 K, 5.79 ERA, 1.23 WHIP | SP #166

2021 ADP: 644.46 (P #592)


It’s been a volatile couple of years for Kendall Graveman, fraught with injuries and the like. Graveman underwent Tommy John surgery in the middle of 2018 and missed all of the 2019 season. He came back to pitch for the Mariners in 2020 before doctors discovered a benign bone tumor in his cervical spine. Given this, Graveman was only able to return as a reliever, given the tumor didn’t allow him to pitch several innings at a time without causing him pain and a marked decrease in performance.

In October, I wrote that Graveman should thrive as a reliever. He’s got the velocity, and he’s said to be working on a slider this offseason, so there’s a lot to be excited about.

Of course, he may continue to not miss very many bats, but he should see a bump in his numbers from his move to the bullpen alone, and, at the very least, he should be a good contact suppressor.


Keynan Middleton (Other Holds Option)

2020: 0 SV, 2 HLD, 12.0 IP, 11 K, 5.25 ERA, 1.50 WHIP | RP #289

2021 ADP: 744.49 (P #834)


When the Mariners acquired Keynan Middleton a month or so ago, I speculated that he was exactly the Mariners’ type, in that they would try and do the Austin Adams or Taylor Williams thing with him. That is, take a pitcher with a good slider and not-good fastball, and have them throw the slider more, and the fastball less.

To further speculate, it feels easy to make the presumption that the Mariners are going to take Middleton’s slider and tweak it to give it a little more depth and bite. As is, it’s a fine pitch, but it doesn’t get many chases outside of the zone.

Perhaps his most underrated (but not best) pitch is his changeup, which seems to have some seam-shifted wake action.

Here’s a gif of his changeup, perfectly executed to Shed Long Jr.:


Middleton has a legitimate chance of becoming a high-leverage reliever that can be depended on.


Anthony Misiewicz (Other Holds Option)

2020: 0 SV, 8 HLD, 20.0 IP, 25 K, 4.05 ERA, 1.30 WHIP | RP #186

2021 ADP: 745.88 (P #854)


Anthony Misiewicz, the lone lefty in the Mariners bullpen, is surprisingly interesting. He leans on a cutter-heavy approach, throwing it 52.7% of the time, while mixing in a four-seam fastball and curveball about a fourth of the time, respectively.

His cutter is something that he throws in the zone with solid results, but he can also use it as a chase pitch, which is quite interesting given that it’s his primary offering. His 22.9% K-BB% seems more like a trait than a one-off thing.


Will Vest (Other Holds Option)

2020: N/A

2021 ADP: Undrafted (N/A)


Perhaps no one is as high on Will Vest as my colleague, Trevor Hooth. He talks about him here and sort of here.

Despite no major league experience, Vest has a ton of upside as a velocity gainer and two secondaries that have flashed above-average. Kyler Peterson said he has the pieces for a potential high-leverage relief role.


Erik Swanson (Middle/Long Relief)

2020: 0 SV, 1 HLD, 7.2 IP, 29 K, 12.91 ERA, 1.70 WHIP | SP #252

2021 ADP: 749.46 (P #961)


I swear this is the last time I’ll say this, but I wrote about Erik Swanson at Lookout Landing and share my thoughts about a path forward for him. Like other Mariners relievers, Swanson has difficulty getting hitters to chase outside of the zone on his secondaries. I suggested that he try his hand at a knuckle-curve or spike curveball, and mentioned a split-change as a less-likely alternative.

As is, Swanson spins his fastball well. He has the perfect fastball for a north-south approach, it’s just that he doesn’t have the pitch to throw south yet. I remain optimistic that he figures it out, but for now, he’s no lock on the roster.


Casey Sadler (Middle/Long Relief)

2020: 0 SV, 5 HLD, 19.1 IP, 21 K, 5.12 ERA, 1.40 WHIP | RP #189

2021 ADP: Undrafted (N/A)


Casey Sadler doesn’t seem like all that much on the surface, but he made a fun tweak in 2020 where, for the first time, he started throwing his curveball as his primary offering. It may just be a blip, but he also had a career-high swinging-strike percentage on his sinker — perhaps because of his pitch mix change. If he maintains his pitch mix from 2020, he’ll be an interesting guy to watch, but his roster spot is also perhaps the most uncertain in the bullpen.


Watch List Considerations


Perhaps the centerpiece of the Taylor TrammellAustin Nola trade for the Mariners, Andres Muñoz will definitely be a player to watch that could serve as a high-leverage reliever. He’s coming off of Tommy John surgery but could return by June if all goes well.

Otherwise, Newsome could spend some time in the bullpen, and perhaps Dunn or Margevicius get pushed there as well. It’s likely Seattle adds another reliever before the season begins.


ADP data taken from NFC ADPs. Pitcher rankings are currently combined. SP and RP positional rankings will be updated when made available.

2020 Positional Rankings from Razzball’s 12-team Player Rater (ESPN).

Photos by Icon Sportswire | Design by J.R. Caines (@JRCainesDesign on Twitter and @caines_design on Instagram)

Michael Ajeto

Michael writes about the Mariners at Lookout Landing, as well as here at Pitcher List. You can follow Michael on Twitter @dysthymikey, or you can not.

One response to “Fantasy Breakdown: Seattle Mariners for 2021”

  1. Keith says:

    What is your take on Yohan Ramirez?

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