Player Profiles 2020: Oakland Athletics Bullpen

Matt Wallach breaks down the Oakland Athletics bullpen for the 2020 season.

The least flashy part of the Oakland Athletics roster may just be the bullpen. Although that doesn’t necessarily mean the unit is bad; they were actually pretty great last season. The group is mostly made up of veterans, and the bullpen as a whole recorded the seventh-best bullpen ERA at 3.89. Their 3.98 FIP was third-best, and their 6.9 fWAR was fourth-best, trailing only the Rays, Yankees, and Twins in that department. The group doesn’t get strikeouts as frequently as those other three teams, though, as their 24.8% strikeout rate ranked 11th in 2019. They tallied 45 saves, most of them coming from their bullpen ace, Liam Hendriks, who experienced a breakout 2019 season. The team’s 109 holds trailed only the Rays’ 116 for the top mark. Yusmeiro Petit and Joakim Soria accumulated the most saves for the team in 2019 as primary setup options, and they are likely to open the 2020 season in those same roles.

Outside of the Hendriks, Petit, and Soria triumvirate, barring any additions this offseason, it will likely be most of the usual options to start the season, with the only notable subtraction being Blake Treinen, who just had a nightmarish 2019 season and was subsequently non-tendered earlier in the offseason. The A’s have a history of operating as a revolving door, usually being active at the deadline to add additional arms, so I’d say it’s likely this unit looks at least a little different come July. As it stands now, I would expect some regression from this group in 2020, but they should still be one of the better units in baseball.


Athletics Projected Bullpen


CloserLiam Hendriks


The best pitcher in this bullpen is without a doubt Liam Hendriks. With 2018 standouts Blake Treinen and Lou Trivino struggling mightily in 2019, it was an unlikely arm who stepped up to pick up the slack. Hendriks was mostly seen as a solid, league-average reliever, and a pitcher who wouldn’t be pitching in many high-leverage spots. In 2019, though, Hendriks made some improvements that benefited him tremendously. Hendriks saw a huge jump in his strikeouts in 2019, up to 37.4% from 21.2%. Easily a career-high for Hendriks, that 37.4% mark was the eighth-highest for a reliever with a minimum of fifty innings pitched. There are two major differences that led to this increase in strikeouts, and I feel because of these tangible differences that Hendriks should be able to make these changes stick into next season. The first main difference was that Hendriks’ fastball velocity spiked. After sitting at 94.7 mph with his fastball in 2018, Hendriks managed to add about two ticks to that in 2019, as he sat at 96.5 mph. This velocity increase likely had something to do with the pitch generating the most whiffs and strikeouts it ever has for Hendriks in his career. That alone is good, but there’s more to Hendriks’ improvements than that. He also changed up his pitch location. He not only got more of his fastballs in the zone, which helped to drive his walk rate down, he also distributed the pitch in a more efficient way. As noted here, Hendriks began to locate his fastball up in the zone, to go along with his breakers down in the zone, a change that I love to see. Being able to effectively change eye levels is a good recipe for success, and that’s also part of the reason why Hendriks set a career high in whiff rate at 36%, up from 25.8% in 2018. His peripherals, such as xSLG, wOBA allowed, and xwOBA, were all in the top 3% of pitchers in 2019.

After being designated for assignment in mid-2018, Hendriks has worked extremely hard to improve his game, and become one of the better relief pitchers in baseball. While he may experience some regression after a 1.80 ERA campaign, I believe the changes he made to his game in the past year should allow him to have success in the future. Hendriks should still remain the anchor of the Athletics’ bullpen, and barring something major like injury or extremely underperforming, he should also remain as their top option for saves in 2020.


Setup Yusmeiro Petit


After a strong 2019 season, the Athletics decided to pick up the team option for Yusmeiro Petit early in the offseason. Now at age 35, we essentially know who Petit is as a pitcher. His 2.79 ERA in 2019 was excellent, although not quite backed up by his peripherals, such as his 3.59 FIP and 4.48 xFIP. While those peripherals don’t paint the most enthusiastic picture of Petit, he still should be a solid reliever in 2020. He doesn’t quite have the strikeout stuff one would expect out of a late-inning, high-leverage arm, but Petit makes it work with a 3.2% walk rate, which was in the top percent  of the league a season ago. Only Josh Tomlin (2.3%) and Chris Martin (2.3%) had lower marks than Petit did in that department. The A’s also have superb infield defense, which should help out a pitcher like Petit a lot. That, combined with a favorable pitcher’s park in Oakland, may be part of the reason why Petit has been able to overperform his peripherals during his previous two seasons in Oakland.

Petit throws four pitches: A four-seamer, a cutter, a changeup, and a curveball. His cutter is thrown almost exclusively to right-handed batters, and the changeup is thrown almost exclusively to left-handers. Those two pitches are his main secondary offerings, with the curveball being used just 14% of the time, and of those two pitches, his cutter generally gets more whiffs, and the strikeout rate for both pitches is nearly identical. Barring any substantial changes, I would expect more of the same from Petit’s pitches in 2020. Ultimately, while Petit may be a good source of holds, there are plenty of relievers out there that will provide consistent holds; the aforementioned Chris Martin would be a great option in this department, and Martin will likely give you the strikeout upside that Petit will likely not. Petit should be a fine reliever in 2020, but just keep in mind that his strikeout output will likely be low, and that could make him a candidate for regression in 2020.


SetupJoakim Soria


Sticking with the veteran theme for the Oakland setup tandem, Joakim Soria is still hanging around as a productive reliever at age 35. Unlike his teammate Petit, Soria is a different type of pitcher, as he gets more strikeouts, and maybe is the pitcher I prefer more of the two. Over the past three seasons, Soria has had a strikeout rate that has been close to 30%, and in 2019, he finished with a 28.4% strikeout rate, only a one-percent decline from the season prior. While a 28.4% strikeout rate isn’t high enough to put him in that top tier of relievers with Josh Hader or Kirby Yates, among others, a close-to-30% rate for a reliever is more than fine. Soria also has decent control, with a 7.2% walk rate, which again, is not elite, but it is more than fine for a setup reliever, and is right with his career averages.

Where Soria regressed in 2019, though, is further in his peripherals. His 3.62 FIP in 2019 was his highest since 2016, with the same being true for his SIERA and xFIP numbers. For additional context, his SIERA was 2.88 in 2018, and that jumped all the way to 3.50 in 2019. I’m not going to panic over a 3.50 SIERA, but it could be telling that Soria’s days as a go-to high leverage option may be nearing their end as he gets up there in age. The jump in those more advanced metrics is likely due to a jump in home runs. For only the fourth time in his career, Soria had a HR/9 rate above 1.0. Not allowing homers was a hallmark of Soria’s game the past couple of seasons, boasting a 0.16 HR/9 rate as recently as 2017. While 2019 was the year of the home run, and a lot of pitchers struggled with the long ball, Soria definitely struggled with it, as evidenced by his 13% HR/FB rate, more than double the mark he set in 2018. That came with a career high in hard contact rate, at nearly 40%, where his previous career high was just 29%. We don’t yet know what the offensive environment will look like in 2020, but if another juiced-ball season is waiting in the wings, Soria will likely continue to have issues with the long ball. For now, Soria is likely to be an average-ish reliever, a source for holds with more strikeout upside than the other current setup option for the Athletics.


MiddleJake Diekman


Acquired by the A’s from the Kansas City Royals before the deadline, Jake Diekman re-signed with the A’s in early December on a two-year contract with $7.5 million guaranteed. For those two seasons, Diekman is likely to fill out the middle innings for the Oakland bullpen. Diekman’s ERA for 2019 was a little inflated for the second straight season, with a 4.65 ERA coming off a 4.73 mark in 2018, again pitching for two teams. It’s also the second-straight season in which his ERA wasn’t matched by his peripherals, as his 3.55 FIP looks much better.

Diekman’s lower FIP comes from a lot of strikeouts and a low number of homers allowed. His 29.8% strikeout rate was his highest since way back in 2014. His 13.8% walk rate is extremely high, and his biggest defect as a pitcher has always been his lack of control, as he’s been in the bottom five percent of all pitchers in terms of walk rate going back to 2015. Excluding 2017, when he only pitched ten innings, that 13.8% rate is the highest he’s allowed since his rookie season in 2012. The other component of FIP, home runs, is where Diekman truly stands out. His 0.44 HR/9 rate is extremely low, only bested by Brandon Workman (0.13) and Kirby Yates (0.30), and he didn’t allow a single home run as an Athletic in 2019. His repertoire consists of mainly four-seam fastballs and sliders, with the majority of his whiffs coming from the slider. His fastball averages close to 96 mph, making him one of the hardest throwing left-handers, and that has actually improved over the past few seasons. Back in 2017, his four-seamer was averaging just under 95 mph, and he has been getting more control over the pitch. His slider has also added nearly 2 mph in 2019 to 85 mph. Diekman’s slider is his best pitch, and while he already uses it nearly as much as his fastball, he could use it even more, as he had a lot of success not just with whiffs, but in getting soft-contact. His 4% barrel rate in 2019 was better than the 7% league average, which I’m guessing has something to do with the increased slider usage in 2019.

With the new rule changes regarding how many batters a pitcher must face going into action in 2020, Diekman will likely not be used in such extreme situations as he may have prior to the new rule. He’s not exclusively a lefty specialist, as evidenced by his shiny new contract, but he will likely face more righties than before, so it’s something to keep in mind. As it stands now, Diekman is likely to be a better-than-average reliever, and with struggles from either of the current setup options, Diekman could slot into that role, which would lead him to become more fantasy relevant.


Middle – Lou Trivino


Another dominant reliever from the Athletics’ successful 2018 season was Lou Trivino, who was working as the setup man for Blake Treinen. The duo was one of the most feared in the league in 2018. Similar to Treinen though, Trivino also fell off quite a bit in 2019.

He started the 2019 season extremely well, with a 1.42 ERA and sixteen strikeouts to just one walk in March/April, but things quickly fell apart after that. Velocity wasn’t the issue, as his fastball still averaged 97.4 mph, exactly where it was in 2018, but instead, he wasn’t getting as many whiffs as he did in 2018. In 2018, he had a 27.4% strikeout rate, which dropped to 21.2% in 2019, with the four-seamer’s whiff rate dropping from 24.1% in 2018 to 17.5% in 2019. The walks also shot up about one percent to 11.5% in 2019, but that alone isn’t enough to explain how his ERA ballooned to 5.25.

Some of his other peripherals are actually better than they were in 2018. He generated more soft contact than he did in 2018, per FanGraphs, and while he did allow more fly balls in 2019, that didn’t result in a higher HR/FB rate, as it actually fell to 10.3% from 14.3%, and he still is primarily a ground-ball pitcher when he does allow batted balls. It’s not quite an easy fix for Trivino, and I’m still not 100% sure what caused his disastrous 2019 season. It would be nice to see his strikeout rate jump back up to where it was previously, and to do that he may need to make more under-the-hood changes, and until we see those changes start to work in games, Trivino will probably have limited fantasy value. However, if he does bounce back and return to his 2018 highs, he could become the primary setup option for the A’s, which would help raise his fantasy value.


Middle J.B. Wendelken


Currently projected to be the youngest pitcher in the Oakland bullpen in 2020, at 26 years old, J.B. Wendelken spent 2019 bouncing between AAA and the majors. In the majors, he produced a 3.58 ERA and 2.94 FIP, with some encouraging peripherals. The righty struck out hitters at a 26.0% clip and kept low walk and home run rates with a 6.9% walk rate, and just a HR/9 of 0.55, allowing just two long balls in 32.2 major league innings. The home runs will likely regress, as he is more of a fly ball pitcher, allowing 51.2% fly balls in his first taste of the majors in 2018, and in 2019 he allowed a similarly high 47.6% fly ball rate, which would have been one of the highest among relief pitchers had he qualified. That low home run rate despite a high fly-ball rate helps explain the discrepancy between his 2.94 FIP and his 4.58 xFIP, as he would be expected to allow more homers with a fly ball rate like that.

His repertoire consists of a four-seam fastball that averages 94.8 mph. He also features a curveball and a changeup as his main secondary offerings, featuring them at rates just shy of 20%. The changeup is his best pitch in terms of whiffs, but is also his worst pitch in terms of wOBA allowed, so I’m not sure if we’ll see the pitch at a higher rate in 2020, although we are still looking at pretty small sample sizes when it comes to his pitches: He only threw 80 changeups to major league hitters in 2019. More encouraging is that he gets great movement — both horizontal and vertical — on his curveball. Setting the minimums to pitchers with at least 50 pitches thrown, Wendelken’s seven inches of vertical movement was fifteenth-best in 2019, and combining that with 3.6 inches of horizontal movement makes him pretty unique among other pitchers. While on its own it doesn’t mean much, it could be an indicator of more whiffs for the pitch in the future. Speaking of the future, with Wendelken now out of minor league options, he should get plenty of opportunities to make a name for himself in the A’s bullpen. If other veterans struggle and Wendelken puts up good results, he should move up in the pecking order. But for now, he’s likely to get mainly middle-relief opportunities until a new opportunity arises.



Watch List 

T.J. McFarland, Daniel Mengden, James Kaprielian 


T.J. McFarland, claimed off waivers by the A’s in early December, is yet another veteran who projects to start the season in their bullpen. The lefty hasn’t had much major league success outside of a strong 2018 season with Arizona, which he hasn’t been able to replicate. With very little strikeout ability, McFarland isn’t going to light up the stat line, but with an elite Oakland defense behind him, he could have more success in Oakland, but is likely to be more of a matchup lefty in a world where pitchers must face three hitters in a row unless the inning ends. That makes McFarland likely to be more towards the back end of the Oakland bullpen, and a possible DFA candidate should reinforcements arrive in Oakland.

Daniel Mengden is projected to be their long reliever with youngsters Jesus Luzardo and AJ Puk moving into the rotation. Like McFarland, Mengden doesn’t project for many strikeouts, and he walked too many batters in 2019 en route to a 4.83 ERA. He’s projected for a 5.11 ERA by Steamer, and like McFarland, could be cut loose with more additions to the bullpen. If you’re desperate for some multi-inning outings, then Mengden may give that to you, although likely without much quality.

Now twenty-five-years-old, James Kaprielian may finally be close to making his Major League debut, and he’s a prospect I’m personally rooting for as a former Yankees first-round pick that I was extremely excited about. He’s been hampered by injuries, missing the entirety of the 2017 and 2018 seasons. He was able to return to the mound in 2019, pitching 68 minor league innings to varying results, but it was more important for him to be healthy after those innings than to get good results. He will likely start the 2020 season in AAA, as it is crucial for him to get more innings, but he could be up in Oakland and making his Major League debut at some point in the summer, and while he likely won’t throw many innings, he should throw quality innings, as he has four high-caliber pitches with a fastball that should sit in the mid-90s.

Photo by Cody Glenn/Icon Sportswire | Adapted by Justin Paradis (@freshmeatcomm on Twitter)

Matt Wallach

Matt studied accounting at UAlbany, is a Yankee fan, and writes for Pitcher List and Rotoballer where he can work with even more numbers to analyze baseball players, which is a lot more fun.

3 responses to “Player Profiles 2020: Oakland Athletics Bullpen”

  1. Alonzo says:

    Good analysis piece! I really enjoyed your article and objective analysis on the A’s bullpen. It’s quite refreshing to see how a good written article sticks to the fundamentals of article writing.

  2. theKraken says:

    There is no better demonstration of the volatility of an MLB bullpen that the 2019 A’s. This would have looked like a complete work of fiction a year ago!

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