Seattle Mariners top ten prospects for 2020

10. Justus Sheffield

Minors (AA, AAA): 133 innings, 7-9 record, 4.13 ERA, 1.353 WHiP, 59 walks, 133 strikeouts

Majors: 36 innings, 5.50 ERA, 1.722 WHiP, 18 walks, 37 strikeouts

There is no questioning Justus Sheffield‘s arm. However, there are numerous questions about his ability to control his arsenal.

The already well traveled lefty has the arsenal and live arm to intrigue any team. Indeed, he has gone from having been selected with the 31st overall selection in the 2014 MLB Draft. He was sent to the Yankees as part of the package for Andrew Miller, and was then sent to Seattle as part of the deal for James Paxton. When he has been dealt, it has been for some of the best players available.

One can easily see why that would be the case. When he is on, he has three above average to plus pitches in his arsenal. Sheffield has added velocity to his sinking fastball since being drafted, with the pitch now sitting in the mid to upper 90s. His slider may well be his best pitch, as it is a nasty strikeout pitch when he can command it. Sheffield’s change lags behind his other offerings, but is another potential strikeout pitch.

The problem is that Sheffield cannot always command his arsenal. He has a high effort delivery, which coupled with the movement his pitches have, can make his ability to spot his pitches come and go. If he cannot command his stuff deeper into games, he could be a dominant reliever. However, the hope is that he can put everything together, and be a top of the rotation starter.

It was not that long ago that Justus Sheffield was top 50 prospect. If he can harness his stuff, he can remind everyone of why he was so highly regarded not that long ago.

9. Kyle Lewis

Minors (AA): 517 plate appearances, .263/.342/.398, 25 doubles, 11 homers, 56 walks, 152 strikeouts

Majors: 75 plate appearances, .268/.293/.592, five doubles, six homers, three walks, 29 strikeouts

Injuries kept the Seattle Mariners from knowing what they had in Kyle Lewis until this past year. Finally healthy, he showed why he was considered such a highly regarded prospect.

Selected with the 11th overall pick in the 2016 MLB Draft, Lewis seemed to deal with injury almost constantly. He appeared in just 30 games that year before suffering a torn ACL, and was held to just 49 games in 2017 due to setbacks and complications. Finally, in 2019, he was able to play a full season, reaching the majors and giving the Mariners a glimpse of the future.

While his speed just has not returned following that injury, Lewis still has the tools that once made him a consensus top 100 prospect. He has a solid approach at the plate, showing an ability to hit with power to all fields. Lewis has a strong arm that would fit well in right, and despite having lost some speed, still has excellent range for the position.

There are obvious concerns. Lewis has been fully healthy for just one season thus far as a professional. He still shows trepidation when it comes to making a sudden move, either on the basepaths or in the outfield. And there is some swing and miss to his game, despite his solid approach.

Yet, the power is there, and Kyle Lewis, if he learns to trust his knee, could once again be a five tool player for the Seattle Mariners.

8. Justin Dunn

Minors (AA): 131.2 innings, 9-5 record, 3.55 ERA, 1.192 WHiP, 39 walks, 158 strikeouts

Majors: 6.2 innings, 2.70 ERA, 16.50 WHiP, nine walks, five strikeouts

One of the pieces acquired by the Seattle Mariners as part of the Edwin Diaz/Robinson Cano trade, Justin Dunn is another pitcher with excellent stuff and suspect command.

Originally used as a reliever in college, Dunn moved to the rotation as a Junior. There, he showed an impressive four pitch repertoire that made scouts fall in love with his potential. Once he showed that he could handle a starter’s workload, it was just a matter of when he would be selected. The Mariners made that pick with the 19th overall selection in the 2016 MLB Draft, adding another intriguing arm to their farm system.

It is easy to be impressed with Dunn. He has a plus fastball that sits in the mid 90s, but has hit 97 MPH. His slider has late bite, and has consistently been a strikeout pitch, especially as he can throw it with varying velocity. Dunn’s curve lags behind the slider, but has shown flashes of at least being an average offering. He also throws a change that has showed some promise against lefties, although it is still a work in progress.

While Dunn has the arsenal to potentially be a middle of the rotation arm, his command and control of his stuff will ultimately determine his fate. He did show improvements in both areas in the minors last season, only to have those issues reappear in his brief major league debut. If that continues, Dunn could ultimately end up as a multi-inning reliever.

Justin Dunn has plenty of potential. However, if he is to reach his ceiling, his control and command of his arsenal will need to improve.

7. Cal Raleigh

Minors (A+, AA): 507 plate appearances, .251/.323/.497, 25 homers, 29 doubles, 47 walks, 116 strikeouts

Cal Raleigh has some big shoes to fill, but so far, the Seattle Mariners top catching prospect appears to be capable of following in the footsteps of the last catcher from Florida State to reach the majors.

Obviously, no one – including the Mariners – are expecting Raleigh to be Buster Posey. However, the third round draft pick in the 2018 MLB Draft has already exceeded expectations, rocketing through the system as he has already reached the AA level. Given the Mariners hole behind the plate, it is not outside the realm of possibility that he finds his way to the majors by the end of the coming season.

While most catchers are a work in progress at the plate, that is not the case here. Raleigh shows an advanced approach from both sides of the plate, working all fields and showing considerable power. He does a good job of putting the bat on the ball, while showing a respectable batting eye.

Although his bat was considered to be ahead of his glove, Raleigh has been a surprise behind the plate thus far. He has displayed an advanced feel for pitch framing, while earning accolades for his ability to call a game. While he may never have the strongest arm, he has thrown out 30% of would-be basestealers in the minors, showing that he can control the running game, at least to a degree.

The Seattle Mariners may have their catcher of the future in Cal Raleigh. If he continues to develop behind the plate, he may be a future star.

6. George Kirby

Minors (A-): 23 innings, 2.35 ERA, 1.043 WHiP, zero walks, 25 strikeouts

Before the Seattle Mariners selected George Kirby with the 20th overall selection in the 2019 MLB Draft, Elon University had never had a player taken before the fourth round. That has obviously changed.

Kirby truly broke through as a prospect during his time in the Cape Cod League, where he excelled as a reliever. He continued that dominance during his junior year in college, especially in the control department, as he issued just six walks in his 88.1 innings. That command continued during his professional debut. Not only did he strike out over a batter per inning, but he did not issue a single walk.

Yet, Kirby is far more than a control artist. The righty has four solid offerings, each of which has the potential to be at least major league average. Presently, his best pitch is his fastball, which sits in the lower 90s, but can tough 98 MPH. As he gains strength, the velocity is likely to improve. His curve and slider both have high spin rates, with the curve looking like a future strikeout pitch. His change has plenty of sink, but still needs refinement.

However, that can be said for all of Kirby’s secondary stuff. He has had a great deal of success with his fastball, to the point where he really did not need to use his other pitches. Although they all flash as possible plus offerings, he still needs to find more consistency with his breaking and offspeed pitches.

Given his command, George Kirby has the floor of a middle of the rotation arm. However, if his secondary pitches improve, he could become an impressive top of the rotation starter.

5. Jake Fraley

Minors (AA, AAA): 427 plate appearances, .298/.365/.545, 27 doubles, 19 homers, 22 steals, 34 walks, 89 strikeouts

Majors: 41 plate appearances, .150/.171/.200, two doubles, zero walks, 14 strikeouts

A somewhat overlooked part of the Mallex Smith for Mike Zunino swap, Jake Fraley could end up being the best piece in that trade.

Fraley impressed at LSU, looking the part of a future center fielder and a possible leadoff hitter. He was eventually selected in the second round by the Rays, part of the Competitive Balance Round B. It was that athleticism that drew the Mariners attention as they have looked to remake their roster.

At this point, Fraley has answered most of the questions about him at the minor league level. He has displayed an ability to drive the ball, particularly when he pulls the ball. Farley has excellent speed and range, which bodes well for him to remain in center. He will need to learn how to work the count and get on base in the majors, but he does have the type of profile that should allow him to do so.

Right now, the biggest question mark about Fraley is his ability to remain healthy. He had not appeared in more than 66 games in a season a profession prior to this year, and still missed time with lower body and thumb injuries.

If Jake Fraley can add a bit more pop, the Seattle Mariners may have a Johnny Damon type of player. Otherwise, he might be a fourth outfielder that intrigues when he plays, but never seems to quite put all the pieces together.

4. Logan Gilbert

Minors (A, A+, AA): 135 innings, 10-5 record, 0.948 WHiP, 33 walks, 165 strikeouts

Stetson University may never be considered a hotbed of baseball talent, but it has produced Corey Kluber and Jacob deGrom. The Seattle Mariners are hoping that Logan Gilbert can follow in those footsteps.

Selected with the 14th overall selection in the 2018 MLB Draft, Gilbert became the highest draft pick in the history of the university. He actually fell to the Mariners, as he pitched through mono during his junior season, leading to an up and down campaign. He did not pitch at all after being drafted, but made up for lost time with a dominant 2019 campaign, advancing through three levels.

Gilbert has a solid four pitch mix, and when healthy, has displayed an ability to command his repertoire. His fastball sits in the mid 90s, and has been clocked at 98 MPH when he reaches back for a little extra. He has a hard slider and a decent curve, with the slider having the potential to be a second plus offering. Gilbert’s change has been effective as well, with solid separation in velocity from the heater.

Given his overall stuff and impressive ability to throw strikes, it would not be much of a surprise if Gilbert continues to advance rapidly through the Mariners system. After making just nine AA appearances last year, it would not be a surprise if he started the season back in Arkansas. However, a quick start to the year could lead to a promotion to AAA, and possibly a look at the majors by the end of the upcoming season.

Logan Gilbert was the highest player drafted in the history of Stetson University. Now, he is looking to follow in the footsteps of a pair of very impressive alumni.

3. Evan White

Minors (AA): 400 plate appearances, .293/.350/.488, 13 doubles, 18 homers, 29 walks, 92 strikeouts

Evan White may have just four games above AA, all of which came in 2018, but that did not stop the Seattle Mariners from locking him in for the long term.

The beneficiary of a surprising six year extension worth a minimum of $24 million, White is seemingly locked in as the Mariners Opening Day first baseman for the coming season. Even if he struggles in Spring Training and needs a month or two in AAA to get ready for the majors, his time is set to come sooner than later.

While signing any player to a long term extension has its risks, let alone one that has never played a major league game, it is easy to see why the Mariners would be willing to take such a gamble. White has an advanced feel at the plate, showing an ability to work the count and make consistent hard contact. Although he is more of a line drive hitter at this stage, he has also made adjustments to his batting stance, lowering his hands as he has worked to tap into his latent power potential.

Defensively, it is thought that White could be a Gold Glove caliber player at first. However, he is more than just a first baseman, having played center for Team USA in 2018. Given that profile, the hope is that he can become Seattle’s answer to Cody Bellinger, although he would need to show more pop in his bat.

The Seattle Mariners are convinced that Evan White is a long term part of their quest to return to the postseason. If they prove to be correct, that early extension will be a bargain.

2. Julio Rodriguez

Minors (A, A+): 367 plate appearances, .326/.390/.540, 26 doubles, 12 homers, 25 walks, 76 strikeouts

Of all the players in the Seattle Mariners system, none may have a higher ceiling than Julio Rodriguez. However, none of their top prospects may have a lower floor.

Considered one of the top ten international prospects in the 2018-19 signing period, the Mariners struck quickly to secure his services, inking him to a $1.75 Million signing bonus. After an impressive debut in the Dominican Summer League, the 18 year old was brought stateside and challenged in full season ball.

Although he missed time due to a hairline fracture in his left hand, Rodriguez showed the tools that made him such a highly regarded prospect. He has incredible raw power, and as his body matured, Rodriguez was able to tap into that power even more last season. With his advanced approach at the plate, he has the ceiling of being a power laden run producer in the middle of the Mariners lineup.

Yet, there is risk with Rodriguez. The biggest concern is that he will continue to expand, going from a muscular power hitter to someone that could eat themselves out of the game. However, he also has displayed a great deal of maturity, which should allow him to reach that potential.

If Julio Rodriguez pans out, the Seattle Mariners will have a star in one of their corner outfield spots. If not, he could end up being a minor league legend, but one who can never make the jump to the majors.

1. Jarred Kelenic

Minors (A, A+, AA): 500 plate appearances, .291/.364/.540, 31 doubles, 23 homers, 20 steals, 50 walks, 111 strikeouts

If the New York Mets do not already regret their trade for Edwin Diaz and Robinson Cano, they will when Jarred Kelenic reaches the majors with the Seattle Mariners.

Already considered a top 100 prospect prior to the 2019 campaign, Kelenic had what may well be his coming out party. The sixth overall pick in the 2018 MLB Draft rocketed through the Mariners farm system, reaching AA by the end of the year. Even more impressively, the 19 year old more than held his own, showing the all around game that has made him a probable top five prospect for the coming year.

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Considered to be one of the top hitters in the draft despite coming out of high school, Kelenic has only justified that lofty rating. His advanced approach at the plate allows him to barrel the ball up, hitting to all fields with authority. While not a speedster, Kelenic has above average speed, and the savvy to pick his spots on the basepaths, making him a possible 30-20 player in the majors. Defensively, he has the instincts for center and the type of arm that would play up in right, making him one of the top five tool talents in the minors.

It would not be a surprise if Kelenic continues his fast track to the majors. He has earned praise for his maturity and work ethic, as he has been considered a workout warrior. Kelenic also has a great deal of charisma, just like his roommate Julio Rodriguez. If both players can reach their ceilings, the minor league teammates could end up being the faces of the franchise.

Jarred Kelenic is not just the Seattle Mariners top prospect – he is also one of the top prospects in the game. His impressive 2019 campaign is only the beginning.