Previewing the '21 Mariners: The bullpen

As terrific as the starting rotation has the potential to be this year, the relief corps has an equal chance to be yet another flaming bag of poo left at the gates of T-Mobile Park. It seems manager Scott Servais and GM Jerry Dipoto think so too, as they're opting to carry eight relievers in addition to the starting six pitchers. Since they do appear to have confidence in the starters, they must be presuming several relievers will be required for most games even if the starter goes six-plus frames.

To be fair to Servais and Dipoto, it's not exactly a storied group of guys here. Much like last season, the ’21 bullpen is a collection of inexperienced youngsters, injury rehabilitation projects, and castoffs from other teams, and not one in the mix can be considered reliable at this point. (The Mariners did sign proven closer Ken Giles to a free-agent contract, but thanks to injury, Giles will be on the shelf for the whole season and won't suit up for Seattle until 2022.) As much as one can crunch the numbers, there's just no predicting what the M's are going to get out of their bullpen with this many mystery arms filling it out; some of them might surprise us, but odds are at least a few won't work out. One thing we do know, however, is that we won't have to worry about the worst of the worst from last season: Dan Altavilla and Taylor Williams are San Diego's problem now.

The final composition of the staff won't be known until training camp winds down, but here are the prime candidates:

  • Erik Swanson could one day become a fearsome short reliever if (a) he's used properly, and (b) he mixes his pitches better than he has been. He's only got two, really, but that can be good enough if he throws his slider enough to keep batters from sitting on his hard fastball. An utter failure as a starting pitcher, Swanson's limited repertoire restricts his effectiveness to an inning at a time, maybe two in a pinch; he needs to air out his high-90s heater to be successful.
  • Left-hander Anthony Misiewicz was one of the best relievers on last year's M's, but that's sort of like saying Moe was the smartest Stooge—faint praise indeed. But he did strike out 25 in 20 innings in 2020 and his FIP (Fielding-Independent Pitching) number was a run better than his ERA at 3.04.
Seattle bullpen, 2020
W-L% ERA SV K/BB BAA/OBA WHIP
.316 5.92 15 1.63 .258/.365 1.556
MLB average bullpen, 2020
W-L% ERA SV K/BB BAA/OBA WHIP
.567 4.44 14 2.35 .242/.329 1.363
  • Converted starter Kendall Graveman is restricted to relief duty thanks to a benign bone tumor in his spine. After spending a month on the injured list last season, he came back as a reliever and found the shorter stints were less painful and easier on his neck; he only threw ten innings in relief last year, but they were effective ones, and with his velocity he could, much like Swanson, find greater success in this role than he had starting. Or the pain could flare up and cause him to lose his command, resulting in fat meatballs that get crushed for home runs. Time will tell.
  • Former Angel Keynon Middleton had been a solid reliever in Orange County before succumbing to the favorite injury of Angel pitchers, the torn ulnar collateral ligament. He underwent Tommy John surgery in 2018 and has only made 24 appearances since, including 13 (12 innings) last season that saw him post an unsightly 5.25 ERA. He seemed fully recovered from TJ rehab, though, throwing hard and feeling, apparently, no pain. He's really not had much opportunity to pitch since his rookie year in 2017, when he was quite good (6-1, 3.86 ERA) in a setup role, and now that he's free of the Angels' injury factory Middleton could be poised to make a nice comeback.
  • 30-year-old Rafael Montero is the early favorite to be the Mariners' closer this year. The Dominican righty was traded to Seattle in December by the Texas Rangers, who didn't see him as part of their rebuilding effort. Yet another pitcher who has returned from Tommy John surgery, the ex-Met missed all of 2018 and part of ’19, making his Ranger debut just before August of that year; he put up good numbers after that as a newly-converted reliever and followed up with eight saves for Texas in last year's mini-season, though the ERA was nothing to crow about (4.08). The knock on him so far is a lack of variety; he throws a four-seamer and a sinker, with a rather pedestrian slider and a too-fast changeup thrown in here and there. If batters get their timing on the fastball there's not enough difference between the four offerings to keep him from getting hit around. Still, he throws strikes and can hit the upper 90s on the radar gun, so, you know, maybe he'll get the job done.
  • Rule 5 draft selection Yohan Ramírez was an adventure on the mound last season, personifying the concept of "effectively wild." In 2023 innings he walked 20, struck out 26, and kept his catchers busy diving to each side of the plate while averaging more than 20 pitches per inning. Somehow he managed to keep his wildness from translating into a lot of runs; his 2.61 ERA was the best on the team despite a walk rate that was worst in the Majors among pitchers who threw more than eight innings (21.3%). His appearances called to mind Nuke LaLoosh from the movie Bull Durham—you can legitimately imagine the catcher quoting LaLoosh's catcher Crash Davis and telling the opposing hitter "I don't know where it's gonna go. Swear to God." Was Ramírez's 2020 success a fluke of luck or some sort of intimidation wizardry? It seems like such results wouldn't be sustainable with that kind of wildness, but as with all of these guys, it remains to be seen if he can get batters out on a consistent basis.
  • After posting decent numbers for the M's in 2019, Brandon Brennan spent most of last year's mini-season on the injured list. When healthy, the right-hander has been an effective ground-ball specialist, something that would play well with the Mariners' stellar infield defense. He only managed one outing before hitting the IL with an oblique injury last year, though he did return to make four appearances  (six innings) near the end of the season.
  • Left-hander Nick Margevicius is vying for a starting role in training camp, but most likely that slot will go to Justin Dunn, leaving Margevicius without a clear role. He could be sent down to start in Triple-A, or he could be kept on the big-league club as a long man out of the ’pen. He impressed at times in 2020, mostly as a starter, and the M's could do a lot worse with their final relief spot. Or, the Mariners might opt for a fresh face in someone like Will Vest, who climbed the minor-league ladder in the Tigers' organization quickly, making all the stops over just two seasons; Vest has taken it on the chin so far in spring training, however, so perhaps a better choice might be Wyatt Mills, a third-round draft choice by the M's in 2017 out of Gonzaga that spent 2019 at Double-A Arkansas (4-2, 4.27, mostly as a starter). Or, more likely, Sam Delaplane, who got a little work in at the Mariners' alternate training site last year after crushing it for Arkansas in 2019 (3-1, 0.49 ERA in 37 innings after a promotion from Class-A Modesto). Another possibility is Matt Magill, who before getting hurt was the only decent option in Seattle's ’pen last season (unscored upon in his first eight appearances); Magill re-upped with Seattle on a minor-league deal and is in spring camp as a non-roster invitee, so there'd be a roster move required if he makes the club.

Next: Catchers and infielders.