The Mariners bullpen, arm-by-arm
Acquiring Gregory Soto from the White Sox may get the Mariners' pen back to elite status.
On paper, the Seattle Mariners bullpen has the look of a top-5 group with the acquisition of right-hander Gregory Santos. The impact of the club’s offseason efforts, however, go beyond Soto, and may ultimately take the club’s relief unit to levels beyond any the club has seen in the last 20 seasons.
Curious why I see it that way? Let’s talk about each arm that may impact the bullpen in 2024.
Andrés Muñoz, RH
4FB: 97-101 (99.2)
2FB: 96-100 (98.4)
SL: 87-91 (88.4)
Munoz induces swings and misses with three pitches, led by the 48.5% whiff rate on his hard slider. He’s also adept at avoiding the home run, but was held back by his control taking a step back last season (10.4%) and a few minor injuries that cut his season to 49 innings.
Munoz is the club’s best-equipped relief arm for high-leverage situations, at least to start 2024.
Matt Brash, RH
4FB: 97-100 (98.1)
SL: 87-90 (88.8)
CB: 84-87 (85.8)
CUT: 91-94 (92.0)
2FB: 97-100 (98.5)
Brash is primarily four-seamer and slider (84.2% of his pitches in 2023), but the curveball has flashed and his cutter was just developed prior to last season, so perhaps he goes to it more in 2024.
The slider is devastating (.162 BAA, .216 SLGA, 48.5% whiff), held back from being the league’s best breaking ball only by below-average command, thanks to inconsistent release points.
The fastball was hit hard in 2023 (.346 BAA, .481 SLGA), but he did stay away from the home run (3) and improved his walk rate by 5.5%. If he can make another meaningful jump in that area, Seattle might have three ‘closers,’ because, well…
Gregory Santos, RH
4FB: 96-99 (97.3)
2FB: 97-101 (98.9)
SL: 90-93 (91.4)Santos’ stuff is ahead of his results so far, including a rather ordinary 22.3% career strikeout rate. But he found the zone a lot more in 2023 (5.9% BB), and his slider produced a pretty nasty line (37.5% whiff, .196 BAA, .203 SLGA). The two-seamer was hit hard in 2023, suggesting there may be a real chance we see more four-seamers from Santos, but he’s bounced between the two offerings without much success, and he’s already throwing the slider 53% of the time.
The runs allowed metrics help project very good performances from Santos, but he must essentially repeat his control numbers from a year ago or find a way to miss more bats. If he does the latter, he joins Brash and Munoz as a three-headed monster that may be unmatched in the American League.
Gabe Speier, LH
2FB: 93-96 (94.4)
4FB: 93-96 (95.1)
SL: 83-86 (84.4)
Speier broke through in 2023, his fifth shot at the big leagues (four with KC), and combined strikeouts (29.6%) with ground balls (55.9%) and control (5.1% BB). He managed versus RHBs (.253/.315/.465) but held lefties to a .218/.248/.287 slash, including just three extra-base hits and two bases on balls in 105 plate appearances.
While he’s best suited as a specialist versus LHBs, Speier can handle down-lineup righties as well as lower-leverage situations. His sinker gives him a chance versus tough right-handed bats, perhaps beyond what he showed in 2023, but it’s imperative he continue to throw strikes, something he did not do in his first two stints in the majors.
Trent Thornton, RH
4FB: 93-95 (94.1)
2FB: 92-95 (93.6)
SL: 79-81 (79.6)
Thornton finds the zone with his fastball-slider combo, the latter of which is his best chance to miss bats. It’s a low-80s, high-spin breaker which may be better if he threw it harder. Both fastballs are vulnerable, but the four-seamer is good enough to set up the slide piece.
Thornton is best suited as one of the final two arms in the pen, covering the middle innings and mostly low-leverage situations.
Tayler Saucedo, LH
2FB: 91-94 (92.3)
SL: 81-84 (82.6)
CH: 85-88 (86.0)
CB: 76-79 (77.2)
4FB: 92-94 (92.9)
Saucedo hides the ball well with a low arm slot and late release behind his front side, and his slider reaps the rewards with a 39% whiff rate. His changeup is his best pitch however (38.5% whiff, .208 BAA, .292 SLGA), and he has always kept the ball in the yard. More strikes would be ideal (11.1% BB), considering neither fastball is overpowering, but there’s some strikeout upside here (in addition to the big ground ball ability) and lefties managed but a .210/.258/.258 slash against him a year ago.
Sauce’s below-average control leaves him best suited for low-leverage opportunities, save for certain matchups versus left-handed batters.
Jackson Kowar, RH
4FB: 94-98 (96.9)
CH: 85-88 (86.6)
SL: 84-88 (86.0)
Kowar has above-average stuff, including a slider and changeup, each with some swing-and-miss ability, and a fastball with shape and a repeatable chance to miss some bats and avoid the long ball. Simple control is a major obstacle and will dictate his chance to see the big leagues and make an impact.
Kowar only fits in the big leagues if he can limit the base on balls, but if he does he’s a three-pitch arm suited for long relief and some middle-innings opportunities.
Ty Buttrey, RH
4FB: 94-98 (96.1)
SL: 81-84 (82.2)
CH: 84-88 (86.2)
Buttrey hasn’t seen the big leagues since 2020 due to retiring in 2021, and then fracturing his finger and cutting short his comeback with the Houston Astros a year ago.
In 2018 and 2019 the right-hander was highly effective, combining for 88.2 innings, well above-average ERA, FIP, and xFIP marks, as well as strong strikeout (27.4%) and walk (7.4%) rates. Since then, control and health have limited his opportunities.
The upside here is probably in a role similar to the one Isaiah Campbell and Matt Festa filled the last two seasons, but there are hurdles for Buttrey to clear if he’s to win a roster spot out of spring training or earn his way to the majors early in the season, especially considering he’s not on the 40-man.
Austin Voth, RH
4FB: 92-95 (93.2)
CB: 75-80 (77.3)
SL: 81-84 (82.9)
CUT: 88-89 (89.0)
Voth is mostly a three-pitch swing arm featuring a four-seamer up to 95 mph and two breaking balls, the best of which alternates depending on the year and role.
None of the three flash much as a strikeout offering, but Voth’ ability to start and cover multiple innings out of the bullpen should not only fit well for Seattle, but T-Mobile Park likely offers Voth the kind of fly ball confidence he’s never had in the big leagues.
Cody Bolton, RH
4FB: 94-97 (95.2)
SL: 82-86 (83.6)
CH: 91-93 (91.7)
Bolton has limited big-league reps (21.1 innings, all in 2023 with PIT), but his high-spin, sweeping slider presents a potential plus offering for a spot role out of the pen. He hasn’t thrown his changeup a lot, but he commands it well and it’s flashed an average pitch. Considering how hard his fastball has been hit above Double-A, it’s sensible to winder if he doesnt end up throwing his slider a lot more with Seattle.
For now, Bolton is depth, but he is on the 40-man, eliminating one potential obstacle in his way.
Mauricio Llovera, RH
2FB: 93-97 (94.5)
SL: 81-85 (82.7)
CUT: 89-91 (90.4)
Llovera lacks a clear out pitch, though he’s flashed an average slider and just added the cutter in 2023. His stuff tends to flatten and offer plane to the batter, but he has done a good job versus right-handed hitters, including a .206/.291/.268 slash against them in the majors last season (110 PAs).
He’s had a split-change in his arsenal in the past and it projected as his best pitch as a prospect, but hasn’t thrown it since 2021.
Llovera projects as depth, and not unlike Bolton has a hill to climb to make the club out of spring training. He does, however, have a track record in the upper minors as a bat-missing righty with some ground ball ability.
Carlos Vargas, RH
4FB: 97-102 (99.4)
2FB: 97-101 (98.8)
CUT: 90-93 (91.7)
Vargas offers big velocity and a chance at a 70-grade cutter that’s missed bat in the minors and his short stints in the majors (46.2%). Similar to Munoz when the Mariners acquired him, Vargas has yet to throw strikes with any consistency, and there are some concerns about the lack of movement on his four-seamer.
There’s work to do but Vargas comes to Seattle with high-leverage upside, For 2024, he’s likely to start the year as depth in Triple-A, tasked with deploying a more consistent set of mechanics.
Eduard Bazardo, RH
4FB: 93-95 (94.3)
2FB: 93-96 (94.6)
SL: 81-84 (82.6)
SPL: 88-90 (89.1)
Bazardo lacks a plus pitch, but generates adequate swing-and-miss with both fastballs and both secondary offerings. He’s always dealth with lefties without forcing the use of his splitter, but it’s a potential third pitch to complete a full array of pitches.
His slider is slurvy with some curveball characteristics and at times looks the part of a strikeout breaker, but he gets short with it rather than burying it or inducing chases to right-handed batters.
He’s on the 40-man and probably has an inside track to one of the eight spots in the bullpen to start the season, but the competition is steep and it’s a thin thread.
Ty Adcock, RH
4FB: 94-98 (96.6)
CUT: 85-88 (86.5)
Adcock debuted in the bigs a year ago, producing mixed results. He threw strikes and limited overall damage, but didn’t miss bats and four of the 11 hits he surrendered were homers.
His cutter — ID’d as a slider by Statcast — needs work, but it’s the lack of shape on the four-seamer that definedAdcock’s big-league stint in 2023. He’s thrown plenty of strikes as a pro, however, lending a chance for value down the road.
The lack of finishing stuff limit his upside, so unless that changes Adcock is depth for the minors.
Heath Hembree, RH
4FB: 92-95 (93.3)
SL: 83-85 (84.1)
Hembree has been wildly ineffective or hurt the majority of the past two seasons, with his velo down a few ticks and his slider lacking the snap. At his best, Hembree was missing bat at a 30% clip for the Boston Red Sox, pitching effectively in high-leverage spots.
He’s a long shot to make the big club, suggesting his best shot is by pitching well enough in Peoria and then sustaining it through his first month or two in Triple-A, awaiting an opportunity.
Brett de Geus, RH
2FB: 92-96 (93.8)
CUT: 87-90 (88.4)
CB: 81-84 (82.3)
de Geus deploys a short-arm delivery offering deception, but his sinker is a contact pitch only and his curveball is fringe average. His cutter has helped him get by and there may be more in the tank there, but the right-hander projects as depth and an up-and-down arm for 2024.
Joey Krehbiel, RH
4FB: 93-96 (94.4)
CH: 84-87 (85.1)
CUT: 86-90 (87.9)
Krehbiel may be a darkhorse for the opening day roster thanks to a quality three-pitch mix which includes a changeup that works some versus left-handed batters. This fact suggests the right-hander can deal with full innings and isn’t a significant disadvantage when a lefty bat comes up. With the three-batter minimum these kinds of things matter.
Could you comment on Corey Abbott and Collin Snider, please.
Great read, small note though. Kaleb Ort isn't in the org anymore. He's with the Marlins now