Everybody wants to find the next great reliever before he achieves that label. This year it was guys like Justin Martinez, Cade Smith, and Justin Slaten who came out of relative nowhere to shut down any and all hitters they’ve gone up against. I do ask that you take most of this with a grain of salt. By virtue of being rookie relievers, they are multiple kinds of volatile. It’s as likely as not that one or more of these guys doesn’t even pitch 10 innings in the majors next year due to injury or poor performance. This is baseball’s equivalent of panning for gold. As such, you sometimes come up with nothing. I’ve got a good feeling about these five though.
Ben Joyce isn’t the only fireballer to come out of the University of Tennessee in the last couple of years. Halvorsen was picked in the 7th round last year by Colorado and climbed up through the ranks of MILB by throwing pure fuel.
Two kinds of fastballs can work in Coors Field. High slot sinkers, and ones thrown faster than the eye can see. Halvorsen fits into the latter category nicely, averaging nearly 100 mph with his fastballs. The shape would be better outside of Coors, of course, and his movement metrics are a bit wonky as a result of his home park, but he should be able to perform well there anyway. It’s not just that he throws hard though, his splitter is a phenomenal offspeed pitch with excellent vertical separation from his fastball. He drops his arm slot substantially to accomplish it but when you throw this hard I’m not convinced that will affect chase rates on the pitch.
He also offers a tight gyro slider that should not be ignored, it will tunnel well with his fastball and provide an excellent third option for him. His “sinker” is odd. He’s only thrown them in away games and I’m not convinced it’s not just that his fastball moves more when it’s not in Coors, though it’s a pretty extreme example. It’s possible he shifts his grip and gets some seam effect movement on it without losing its general shape. It’s a small sample though and thus could just be noise. Regardless, Halvorsen has an overwhelming arsenal of three easily plus pitches that could lead him to be one of the best closers the Rockies have ever had.
Bear with me for a moment here. This guy is a mix of two high-profile pitchers in one. He’s had a long and tumultuous journey to the big leagues, in which he’s spent a lot of time injured and battling command issues. This is going to sound even more concerning when I tell you he averages 92.5 with his fastball as a non-sidearm pitcher. Again, just bear with me.
So rather than play a guessing game, I put them next to each other for comparison. Neither are exact matches, but they’re close enough that it stood out to me immediately. His fastball has world-class vertical movement from an average release height. While his over-the-top arm slot would lead hitters to expect the movement direction it has, nothing prepares them for just how much it moves. Sabrowski and Vesia are the only two lefties to average 20” of iVB this season. He pairs it with a cutter-ish slider that should still miss bats due to its spin and relationship to the fastball despite its lack of depth. And for the finishing touch, a big 12-6 curve that mirrors his fastball and baffles hitters with its shape. He also hides the ball behind his body until late in his delivery, adding deception to his pitches. I am not saying he is some kind of god-tier hybrid pitcher, only that he resembles some other pitchers with excellent pitch traits, and that bodes well for him.
Bigge is probably one of the better-known arms on this list but we’re covering him anyway because his stuff is incredible. His command of said stuff is a work in progress but I can’t not bet on talent like this.
Bigge’s fastball is a phenomenal base for an arsenal, an easy 70-grade pitch with velocity and exceptional rise from a unique release point. It’s the prototypical relief ace fastball. His second most used pitch is his faster gyro slider which, again, is pretty standard for a great reliever. It plays well off his fastball the way you would expect it to. What makes Bigge so interesting is his developmental third and fourth pitches as they could give him excellent depth to his arsenal as well as a pitch for all situations. The sweeper is frankly unfair, having a pitch that moves that much in the mid-80s is a mean thing to do to same-handed hitters. And to top it off, his curveball is pretty good too, combining power and great movement. The Rays have once again looked to the Cubs for an underrated reliever and potentially struck gold, again.
Sticking with the Rays, you’re going to have to once again bear with me, because we’re working with a very small sample. Montgomery has only thrown 5.2 MLB innings. He also has only shown two pitches so far. He’s been a starter for most of his career but made a move to the bullpen after a terrible start to the season in AAA. The Rays might move him back to the rotation at some point, but they might have found a good thing with Montgomery working short outings.
Lefties that throw 97, even in relief, are still a rarity. Those that do so with an excellent shape are even harder to find. Montgomery gets behind the ball and just rips anti-gravity balls in the high 90s, which of course will play up further with his being left-handed. There are only 8 lefty fastballs that have been thrown with more vertical movement on average than Montgomery’s this season, and he throws harder than all of them. The only other pitch he’s thrown so far is a good gyro slider in the high 80s, which is pretty much exactly what you would expect him to pair with that fastball. His velocity has ticked up substantially since moving the bullpen, and it’s unrealistic to expect this stuff to hold if they moved him back to the rotation. He has a changeup he used as a starter but he doesn’t seem to need it in relief. Both of his pitches are well-suited for opposite-handed hitters anyway. Regardless, stuff like this near automatically puts Montgomery in future closer conversations.
So I saved my favorite for last. Guerrero probably isn’t the best reliever of the bunch here, but he’s just so much fun to watch. We’re again working with a pretty small sample but I can’t ignore what I’ve seen from him so far.
Guerrero’s fastball looks better than it is, but it’s still solid. He throws hard but as a short-strider gets minimal extension. He gets a lot of movement but it’s a generic shape from a generic release. It will probably play a bit closer to average than it looks like it should but this is also his weakest pitch. Guerrero seems to be aware of this as he’s already employing a secondary-heavy approach. He should lean into it even harder as time goes on as his non-fastballs are the real weapons. His sweeper is excellent, nearly a foot of horizontal break at 86 will nearly always play well. The pitch that made me notice him though is his changeup. This pitch is nasty. 9 mph of velocity separation but still thrown hard at 89, and a foot of vertical separation, while fading a foot and a half. It’s a gorgeous changeup and he should work it in more.
Final Thoughts
As much as I like all of these guys, odds are they won’t all see immediate success. I think Bigge and Halvorsen are probably the best bets for next season, but all of these guys should be on their way eventually. Again, these are all closer to long shots than sure things by nature of their role and experience, but such is the game. All that’s left is to wait and see if we’ve found the next big thing before everyone else.
Interesting stuff but especially when writing about obscure players like Sabrowski and Guerrero it never hurts to say what team they play for. (And FWIW when it comes to future Guardians dominance some might argue Andrew Walters instead.)