Yusei Kikuchi, Seattle Mariners

Unless regular-scheduled programming is preempted by an agreement between the owners and the MLBPA, the Seattle Mariners, and 29 other clubs, are due to report for spring training in the next several days.

This suggests at least a near-complete list of report-date rosters, so let’s go through this group by group.

Projected Starting Rotation

With the Mariners sticking with a six-man rotation, much to the apparent chagrin of one Marco Gonzales, bless his heart (I agree with him), it looks like their six are already in camp — barring a last-second free-agent addition or trade that ultimately upgrades the unit, which isn’t a far-fetched possibility.

Marco Gonzales
SNK: 87-90 (45.3%) CUT: 84-86 (24.3%) CB: 74-77 (16.1%) CH: 80-82 (14.4%)

One of the more underappreciated players in baseball, Gonzales is coming off 3.5, 3.7 and 2.0 fWAR season, the latter in just 11 starts.

It’s plus-plus control, plus command and two above-average pitches, including a cutter that allows him to pitch effectively on the edges versus right-handed batters. His changeup is typically at least average and has flashed plus, but he didn’t even have it for most of 2020.

It’s a unique skill set in 2021, but Gonzales induces weak contact by punching the entire strike zone with his variety of stuff, despite the lack of velocity. His sinker doesn’t induce ground balls (8.5% of balls in play in 2020) and he doesn’t generate a lot of swings and misses (8.4%) with anything.

Gonzales is the left-handed Kyle Hendricks, and it’s about time folks start realizing it.

UPDATE: The Mariners’ signing of Paxton changes the rotation projection.

James Paxton
(2019) 4FB: 93-97 (53.7%) 2FB: 93-96 (6.2%) CUT: 84-87 (20.2%) CB: 80-83 (18.6%) CH: 84-87 (1.2%)

Paxton made just five starts in 2020 but was up to 94 in a workout in late December in front of several clubs. When hes right, he’ll live at 95-plus and dominate with a plus knuckle curveball and keep-honest cutter-slider. At times the cutter is plus, too, and he’s flashed a useful changeup.

Seattle gave him $8.5 million guaranteed, so we can assume they believe he’s healthy and will start the season as one of their six rotations arms.

Yusei Kikuchi
4FB: 93-97 (37.5%) CUT: 91-94 (39.9%) SL: 82-85 (16.0%) CH: 85-88 (6.3%)

Kikuchi took a step forward in 2020, posting a 3.30 FIP in nine starts. While his control took a few step backs (10.3% walks versus 6.9% in 2019), his strikeout rate went up 50% to 24.2% and he posted a 12.1% swinging strike rate, up nearly four percent from the previous season.

He also induced more ground balls by nearly eight percent, perhaps as a result of the increased use of the cutter, which was classified as a slider in 2019.

The slider he used in ’20 was a better version, nearly three miles-per-hour slower, and he ditched the mid-70s curveball, which looked pretty but was a hanger waiting to happen.

In general, Kikuchi needs to throw more strikes, particularly early un counts to avoid 2-0 and 3-1 counts, and if he could get a bit more from his changeup and slider we could look up at the end of the season and see an average or better 26-28-start season.

Justus Sheffield
SNK: 91-95 (47.2%) SL: 81-84 (33.5%) CH: 85-88 (18.4%)

Seattle has essentially turned Sheffield from a thrower to a pitcher. He’s using a sinker instead of a four-seam fastball and it’s helped the lefty stay off the barrel and continue to generate ground balls.

The slider is plus and a legitimate mid-level swing-and-miss offering, and the changeup had its moments and was regularly a part of his attack.

The next step for Sheffield is command. He improved his ability to throw strikes with a more consistent, athletic delivery in 2020 versus 2019, but locating his fastball better, particularly versus right-handed batters, sets up the southpaw for a strong mid-rotation role.

Chris Flexen
4FB: 91-95 SL: 85-89 CB: 77-80 CH: 82-85

Flexen spent 2020 in the KBO and enters 2021 as a rather large unknown in terms of how his stuff will play versus big-league bats.

Flexen is built like a starter and has the delivery for it, bit in his time with the New York Mets (2018-19) he was used in relief and had problems throwing strikes in short stays. His numbers in Korea line up with his minor league performances, though, so it’s not entirely out of line with his abilities, at least in terms of throwing strikes.

He used his curveball a lot more last season, which appears to be a big reason why he had success in 21 starts (2.74 FIP, 116.2 IP). Whether it’s a swing-and-miss pitch in the states remains to be seen, but Seattle is committed to giving him a chance to start for the long haul.

The good news is, the raw stuff suggests it should at least be fun.

Justin Dunn
4FB: 90-93 (53.8%) SL: 82-85 (15.2%) CB: 78-81 (23.8%) CH: 86-88 (6.0%)

Dunn battled in 2020, but barely survived innings and starts. He ended the year with a FIP and xFIP over six, a 45% hard-hit rate and 19.2%-15.7% strikeouts-to-walks comparison. Too many walks and hard-hit balls, and not enough strikeouts, especially considering the flyball stuff.

The lazy projection here is to banish Dunn to the bullpen, but I’m not sure that’s the answer for the right-hander, who saw his fastball dip a full tick, sometimes two, from mid-season 2019 to late-season 2019 and all of 2020.

Velocity isn’t the only issue, however. Neither breaking ball looked better than fringe-average and there’s no semblance of a useful changeup.

Not pretending to know what Seattle plans to do with Dunn, but unless there’s significant improvement shown in March he’ll warrant a trip back to the minors. Dunn’s stuff must become more consistently competitive to last in the majors.

Rotation Depth

Nick Margevicius
4FB: 88-92 (64.1%) SL: 83-86 (15.8%) CB: 69-72 (11.4%) CH: 81-84 (8.7%)

Margevicius, who won’t turn 25 until June, and added two mphs to his fastball in 2020, touching 93 and seeing 91-92 just about every time out, starter or reliever.

It’s a legit four-pitch mix with average command and above-average strike-throwing, but there’s no sign of an out pitch and the stuff has flyball tendencies. Essentially, Margevicius is a poor-man’s Marco Gonzales, but with some upside considering age and physical projection

I like Margevicius as a sleeper if he’s given the chance to start consistently. He may get that chance from the outset in 2021 if Dunn is moved to the bullpen or shipped to Tacoma early.

Ljay Newsome
4FB: 90-93 (49.4%) CB: 76-79 (26.7%) CH: 83-86 (23.9%)

Newsome held his velo this past summer, which is a good sign it’s here to stay after the right-hander built up his arm strength and arm speed in 2019.

The stuff was rather ordinary in 2020, but he focused on a three-pitch attack and pounded the strike zone. He’s shown a cutter in the minors which may be unveiled in 2021 in attempt to compete better versus left-handed hitters, who crushed him in 2020 (.379/.400/.724) in 30 batters faced. We also didn’t see the good changeup much, which impacted his ability to pitch to lefties, too.

I don’t see a good chance the stuff ticks up enough for a high-value relief role, but a valuable swing arm or back-end starter remains within his projection.

Robert Dugger
SNK: 91-93 (10.8%) 4FB: 91-94 (42.9%) SL: 80-84 (26.9%) CB: 75-78 (16.5%) CH: 83-85 (2.8%)

Dugger could find himself in a relief role where he may have a better chance to see the majors in 2021 for Seattle, but he’s primarily been a starter with mixed results, both in the minors and in the show.

He has 45 big-league innings the past two seasons but ha shad problems missing bats and keeping the ball in the yard, a combo with which pitchers never want to be associated.

Dugger is athletic with good arm speed. The curveball is above-average with two plane break and the slider flashes as a weapon. It’s a power arsenal but without the big fastball, though there’s good run to his arm side and he gets some ride up in the zone, too.

As a full-time reliever we could see a bigger uptick in velo, so keep an eye on that this spring.

Logan Gilbert (NRI)
4FB: 92-96 CB: 75-78 SL: 81-85 CH: 84-87

Gilbert doesn’t have great stuff, but it’s good, and it’s consistent, as is his present 50-grade command. The changeup still lags behind both breaking balls, but there’s a foundation there and it will flash above-average.

He’s built like a frontline arm and despite less-than-elite velocity, he will touch 96-97 at times and simply needs to show he can stay out of the middle of the zone, both vertically and horizontally.

He’s unlikely to make the club out of spring training, but as long as he’s healthy he’ll see a lot of innings in the majors in 2021.

Roenis Elias (NRI)
4FB: 93-96 (50.9%) SNK: 92-96 (4.8%) CB: 76-79 (13.3%) CH: 85-88 (29.1%)

Elias opted out last season and split 2019 between the Mariners and the Nationals. He was traded to Washington with RHP Hunter Strickland in exchange for RHP Elvis Alvarado, and lefties Taylor Guilbeau and Aaron Fletcher.

His arm should be fresh and his changeup has been more of a weapon for him the past two seasons. Elias is the most likely NRI to make the club.

Darren McCaughan (NRI)
4FB: 90-94 CB: 77-81 CH: 84-88

McCaughan’s stuff suggests relief work, as does the delivery. He throws a lot of fastballs and the secondaries need a lot of work from an aesthetic standpoint, but he hides the ball well and the movement on the hard changeup is late and to his arm side.

He also throws from a lower arm slot — I’d call it slightly below 3/4 — and might offer a chance at a good sinker-slider combo if the club points him in the direction of relief work.

Ian McKinney (NRI)
4FB: 88-93 CB: 75-78 CH: 81-84

McKinney is undersized but repeats his delivery well and owns what might be the best curveball in the organization — including the top prospects and current big-league arms. His fastball sits 89-91 mph, but will touch 93 with life, and plays up thanks to a deceptive delivery.

McKinney’s changeup is useful, too, and he’ll live on the outer edge versus right-handed batters with all three pitches. He throws strikes and can locate the breaking ball. His severe reverse splits create some fog in his projection.

Either way, the size and stuff suggest swing arm or multi-inning reliever, but there’s pitchability and playable stuff here if deployed strategically, and 2021 could be the year he gets a shot. Keep an eye on McKinney as a bullpen option.

Projected Bullpen

I’ll go eight deep here, even with a six-man rotation, since the roster will be at 26. We may even see times there are nine relievers, which is too many, but until the league adds a pitcher limit this is the world in which we live.

Rafael Montero
4FB: 94-98 (49.5%) SNK: 94-97 (24.2%) SL: 85-88 (7.3%) CH: 88-91 (20.8%)

Montero is a fastball-changeup arm, using two heaters in 2020 to mix up the movement and allow him to pitch to more areas of the zone effectively.

He was very good versus both lefties and righties in 2020, though RHBs got him for decent pop (.452 SLG). This is where the below-average slider impacts the results and puts more pressure on Montero’s fastball command.

He’ll get the first shot to serve as closer, though I sense the Mariners may deploy their bullpen a little differently in 2021 than in years past. If so, Montero will see more time in the 8th inning instead of being saved for the save.

Kendall Graveman
4FB: 93-97 (8.5%) 2FB: 93-97 (59.6%) CUT: 89-92 (9.7%) CB: 78-81 (5.5%) CH: 87-90 (16.7%)

I still prefer Graveman as a starter, but his injury appears to be the driving force to relief work. In order to make it work, we may see the veteran pare down his arsenal a bit, and could see an increase in four-seamers — or fastballs in general — up in the zone.

The curveball is his worst pitch — and his least used — so unless there’s a plan involving improvement with that offering, it may be the first to go.

Graveman is difficult to project for lack of experience in a bullpen role, but as a starter he’s been hit pretty hard, hasn’t missed bats, and his ground ball rate was down to 48.1% last season.

I think of Graveman as the Wild Card for the Mariners; if his stuff ticks up and he’s able to find more whiffs, he could be Montero’s main setup man. Otherwise, and most likely, he’ll fit a multi-inning middle role who shouldn’t be asked to dig the club out of tough situations.

Keynan Middleton
4FB: 95-99 (59.0%) SL: 86-89 (22.4%) CH: 87-90 (18.6%

Middleton’s intrigue starts with the fastball, which is occasionally into triple digits with elite spin rates, suggesting there may be room to miss more bats with it. He does a good job avoiding the barrel and both secondaries produce swings and misses.

He hasn’t remained health since 2017 thanks to Tommy John surgery and at least one significant setback in his recovery, but the velo was back in 2020.

Control has held back the right-hander, too, starting with a career 10% walk rate.

Anthony Misiewicz
4FB: 92-96 (24.4%) CUT: 89-91 (52.4%) CB: 81-84 (23.2%)

Misiewicz has good enough stuff to turn into a Swiss Army Knife option out of the bullpen, covering multiple innings and dominating left-handed batters (.216/.256/.243 in 2020). He struggled versus right-handed hitters, however, enough to suggest he’ll need to be better to warrant such a role, or even more than a bridge in the middle of the game.

Only five relievers in MLB used their cutters more than Misiewicz, but that’s certainly not a bad thing, in and of itself. Perhaps more curveballs — his best swing-and-miss pitch — can help, but this may be about fastball command.

For now, he remains one of the more reliable arms in the Mariners bullpen, and carries some upside into the season — his first full year in the big leagues.

Casey Sadler
2FB: 92-95 (35.3%) CUT: 88-90 (23.0%) CB: 79-82 (37.1%)

Sadler flashed a bit the past two seasons split between four clubs, but saw a spike in swinging strike percentage to 12.9 in 19.1 innings a year ago and that rate held steady in seven appearances with the Mariners in September.

The curveball is the out pitch, posting 44.4% whiff rate and 28% put-away rate in 2020.

He’s out of options, so if it’s a close race for one of the spots, Sadler may win out as a result, but he might just be a solid middle reliever if he can get enough from his fastball and cutter to get the the curveball with two strikes.

Yohan Ramirez
4FB: 94-97 (59.8%) SL: 81-84 (40.2%)

Unlike a year ago the Mariners can option Ramirez to Triple-A for more work and there’s certainly a chance they do that from the get-go in 2021. The next veteran reliever signing to guaranteed dollars may very well suggest that’s the plan, if the club isn’t there already.

Ramirez is athletic with a loose arm and he’s up to 98 mph with the fastball. There’s life on the pitch and enough of it to avoid the barrel, setting up a slider that carries plus upside (43% whiff, 27% put-away).

Even fringe-average strike throwing likely turns Ramirez into a setup type, but he walked 21.3% of the batters he faced in 2020.

Will Vest
4FB: 93-98 SL: 85-88 CH: 83-86

As a starter in the Florida State League back in 2018, Vest was 92-94 mph with a two-seamer, backed by a power slider at 84-86 and developing changeup,

Since then, in relief and employing a more aggressive approach and delivery, the velocity has ticked up (mostly 94-96, but some 97-98, reportedly), the slider has more shape, and the changeup is more consistent with better velocity differential off the fastball.

He’s athletic, and the delivery has become repeatable, suggesting there’s stuff and command growth to follow, which, in turn, suggests Vest has a good chance to not only stay up all season as a Rule 5 pick but help the Mariners bullpen and project well for the future.

One scout told me if the slider keeps going in the direction it is, it’s plus, and Vest is a legitimate three-pitch option.

Erik Swanson
4FB: 94-97 (74.5%) SL: 87-89 (17.4%) CH: 81-84 (6.7%)

Swanson is a bubble arm to start the spring and has options left, but he flashed at 99 mph last summer to prove the arm strength is there for a successful transition.

But he’ll need more than velocity to get there; the slider is well below average, the control is fine but the command is not and we’ve yet to see him string together consistent outings.

I’m curious about the development of the changeup, which, even if not a plus offering, could help relieve the stress on everything else, but first and foremost on the lost of things to do has to be getting that slider up to par.

Bullpen Depth

Brandon Brennan
SNK: 92-95 (31.8%) CH: 82-85 (38.5%) SL: 85-88 (37.6%)

A healthy Brennan is a favorite to make the club, so he’s only down in here because, well, he missed most of 2020 part of 2019 with injuries.

But he also has has issues throwing strikes consistently, rolling out a 12.2% walk rate in 44 games back in 2019, the last available qualifying sample.

When he’s right, Brennan is consistently 92-94 mph with armside run and sink and a plus changeup that flashes plus-plus. Both pitches induce ground balls at a high rate.

Brady Lail (NRI)
SNK: 89-92 (20.0%) CUT: 84-87 (15.3%) CB: 78-81 (19.3%) CH: 85-87 (15.0%)

Lail reminds me some of Nick Vincent, sans the high-zone four-seam fastball value that essentially made Vincent what he was. Lail’s mix is fringey, but the curveball, changeup, and sinker are average pitches.

Considering the ordinary stuff, Lail’s control and command need to be better. He’s walked 10% of the batters he’s faced as a major leaguer, and with no swing-and-miss pitch it’s all about weak contact.

Joey Gerber
4FB: 92-95 (27.5%) SNK: 92-95 (37.8%) SL: 83-86 (34.8%)

Gerber’s stuff didn’t show well in the big leagues last season; I’ve seen him 93-97 with more arm side run and a better slider. If he’s going to make the club and eventually stay in the majors he’ll need the slider to pitch away from right-handed batters and induce whiffs.

Gerber’s 9.7% strikeout rate screams the need for adjustments, but he did keep the ball in the yard, as he has in the minors, and there’s likely more of which to take advantage with his deceptive delivery, so I still think he’s a quality arm, he just happens to be one without high probability to start 2021 hot — or in the bigs.

Domingo Tapia
4FB: 96-101 (38.8%) SNK: 97-101 (37.5%) SL: 85-88 (18.8%)

Tapia, who also has a nearly-never used low-90s changeup, is all arm strength at this point. He does get some swings and misses from the heater, though, so it’s a great place to start.

Problem is, he’s 29 and the slider as been stagnant for years, so it appears it will take a brand new idea to get a second pitch into the holster.

Aaron Fletcher
SNK: 92-95 (65.3%) SL: 80-83 (21.5%) CH: 79-82 (13.2%)

Fletcher’s stuff outweighs his present ability to execute it effectively. In the minors, the lefty pounded the strike zone with his fastball and swept the slider for some whiffs and called strikes.

There’s deception in the delivery but he needs to repeat to become a factor and ultimately use the secondaries more often.

The bullpen may be comprised of a starter such as Newsome or Dugger if they don’t make the club as a starter, and Andres Munoz is expected to be back over the summer; Munoz was acquired from the San Diego Padres in the trade that sent Austin Nola to the NL West.

Sam Delaplane
Delaplane is a reliever-only fastball-curveball arm likely built for short outings. The four-seamer is up to 95 mph and the curveball is a tight spinner with downward break, potentially a swing-and-miss pitch.

Wyatt Mills
Mills is a sidearmer with a sinker-slider combo. He’s up to 97 mph and comfortably 92-94 with natural sink and run.

Juan Then
Then is still on track to see the rotation in Modesto, but could move quickly in a relief role. He was up to 99 mph in the fall and his slider has sharpened since the trade from the Yankees.

Gerson Bautista (NRI)
Coming off injury, Bautista is looking to get his velocity back, but also show vast improvement to his control. The slider is average or better and he misses bats with a 94-99 mph fastballs.

JT Chargois (NRI)
The sinker-slider righty is up to 98 mph and whiffed 31.8% of the batters he faced in 21.1 innings with the Los Angeles Dodgers in 2019. If he’s healthy and throws strikes in March, he’s making the club.

Nick Duron (NRI)
The 25-year-old is a loose-armed right-hander up to 96 mph in relief. He has a low-to-mid-80s sider and a 40-grade changeup he doesn’t use much out of the bullpen. More likely to serve as depth in Triple-A.

Moises Gomez (NRI)
Gomez, 24, came over from the Twins organization. He’s 95-99 mph with an average slider, and has always missed bats. He’s a pure reliever likely set to start the season in the upper minors, but if he finds a way to throw more strikes he could find his way to the majors by year’s end.

Taylor Guerrieri (NRI)
Sinker up to 96 mph, curveball, and changeup, but the right-hander has battled injuries on his path to the big leagues. Spent 2020 with the Texas Rangers (5.38 FIP, 22% K, 18% BB), putting up good ground ball numbers.

Matt Magill (NRI)
At times, Magill was the Mariners best reliever in 2019, especially the second half of the season once GM Jerry Dipoto had traded away the seasoned veterans in July. Fastball up to 96, above-average curveball, average cutter. If healthy, good shot to make the club.

Vinny Nittoli (NRI)
Nittoli is now 30 and has yet to make his big-league debut, but he’s up to 95 mph and pitches well up in the zone thanks to some run and ride. The slider is at least average and breaks late, and the curveball flashes, too.

Paul Sewald (NRI)
The four-year veteran is 91-94 with a slider and changeup. He was serviceable 2017-2019, but struggled in five outings last season.

Drew Steckenrider (NRI)
The 30-year-old didn’t pitch in 2020, but lives in the mid-90s with a power curveball. He needs to find the zone more consistently, but the raw stuff is there.

Jimmy Yacabonis (NRI)
The right-hander is up to 95 with a two-seamer to set up a projectable slider and fringe-average changeup.

Penn Murfee
Murfee’s neither on the 40-man roster nor on the non-roster invitee list, but I think he should be. He doesn’t throw hard, but is another sidearmer with command and a good slider. In relief the fastball may tick up a bit.


Last Updated on February 14, 2021 by Jason A. Churchill

Image courtesy of Nick Wosika/Icon Sportswire
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Jason A. Churchill

Churchill founded Prospect Insider in 2006 and spent several years covering prep, college and pro sports for various newspapers, including The News Tribune and Seattle PI. Jason spent 4 1/2 years at ESPN and two years at CBS Radio. He now serves as the Executive Copy Editor at Data Skrive, a tech company that manipulates data to provide automated content to clients including the AP, BetMGM, USA Today, and ESPN. Find Jason's baseball podcast, Baseball Things, right here.