Updated Top 10 Prospects (2019): Seattle Mariners: Where Do The Pieces Acquired In The Cano/Diaz Rank (Kelenic & More)?

by Eric Stashin (aka The Rotoprofessor)

The Mariners have been an aggressive team in terms of making deals, and to an extent it has left their farm system somewhat barren…  That was before a few deals have helped to restock their system, acquiring their newly minted top two prospects in trades for James Paxton and more recently the blockbuster sending Robinson Cano and Edwin Diaz to the New York Mets..  Even before the deals there was upside to be found, but it came full of questions.  As the team appears to be headed towards a rebuild it wouldn’t be surprising to see the system continue to change dramatically as the offseason progresses, though time will tell.  With that in mind, let’s take a look at how things currently stand:


1) Justus Sheffield – Left-Handed Pitcher
Grade – B+
ETA – Already Arrived

Sheffield made three appearances out of the bullpen for the Yankees last season (2.2 IP), but he should get an opportunity to slot into the rotation for the rebuilding Mariners.  Splitting time between Double and Triple-A last season he posted a 2.48 ERA and 1.14 WHIP while showing impressive strikeout stuff (12.4% SwStr% leading to a 9.54 K/9).  That’s not to say that there aren’t questions, however:

  • Control – 3.88 BB/9 (3.68 over 88.0 innings at Triple-A)
  • Groundballs – 43.8%

Throw in being listed at 6’0″, shorter than generally desired for a starting pitcher, and there is some risk though he will benefit from getting out of Yankee Stadium and the AL East.  There’s no questioning the upside, it’s just a matter of overcoming the obvious risks.


2) Jarred Kelenic – Outfielder
Grade – B
ETA – 2021

By most accounts the Mets got a bargain when they selected Kelenic sixth overall in the 2018 draft and he certainly impressed upon starting his professional career by hitting .286 with 6 HR (as well as 10 doubles and 6 triples) and 15 SB over 220 AB playing for two levels of Rookie Ball.  Regardless of the level, for a player of his age and experience level seeing a 9.7% SwStr% and 10.4% walk rate are highly impressive and shows that he has an advanced feel.

Still just 19-years old there are concerns that the speed will slow as he matures and he will need to move to a corner outfielder spot.  Obviously he has a long ways to go in his development, but seeing him mature into a 20/15 player with a strong average is very realistic.  You will need to take a patient approach, but the upside is there.


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3) Kyle Lewis – Outfielder
Grade – B
ETA – 2019

The question with Lewis is his health, as knee issues have plagued him since being selected in the first round of the 2016 draft.  Those concerns significantly drag his grade down, as we are left to wonder if the knee issues will ultimately rob him of his ability to generate power.  He hit just 9 HR over 328 AB between High-A and Double-A last season, while hitting .244 as he struggled to make consistent contact (13.5% SwStr%).  If healthy the approach is obviously strong and should translate well:

  • Line Drive Rate – 24.8%
  • Oppo% – 34.3%

The strikeouts are a significant concern, as is the risk of his power not fully developing.  He also was never a burner to begin with, so consistent knee problems are also going to help cost him the ability to carry an elevated BABIP.  There’s obvious upside, but right now the value may be at an all-time low.



4) Evan White – First Baseman
Grade – B
ETA – 2020

The team’s 2017 first round selection spent the bulk of last season at High-A, with a cameo at Triple-A (18 AB), showing signs of potential.  While at High-A he hit .303 while keeping the swings and misses at a minimum (9.8% SwStr%).  However at his age (he played the year at 22-years old) and at the level he was playing, is that enough to excite anyone?  Then you have the questions about his power, hitting 11 HR while adding 27 doubles and 7 triples.  He needed a .363 BABIP to gethis strong average, and with the potential for the strikeouts to rise these other numbers increase the concerns:

  • Groundball Rate – 48.6%
  • Pull% – 48.5%

The potential is there for him to grow in the power department, and that would go a long way in his development.  Right now there are questions, but a strong showing will raise his grade at least a half grade (think of him as having a “B+” type prospect).


5) Julio Rodriguez – Outfielder
Grade – B
ETA – 2022

Those who are looking at Rodriguez are going to take a patient approach, as he played 2018 as a 17-year old (he turns 18 in December) in Rookie Ball.  The potential is there, though, as he hit .315 with 5 HR and 10 SB.  For a player his age, having added 13 doubles and 9 triples shows that the power potential is there and should develop in time (especially as he fills out his 6’3” frame).

Regardless of the level, an 11.8% walk rate is something to work with and shows the approach.  Granted a 23.0% SwStr% is eye-popping, but again we’re talking about a 17-year old kid who is still learning and developing (and have years before he fully taps into the potential).


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The Rest
6) Justin Dunn – Right-Handed Pitcher (Grade – B-)
A college reliever, the Mets had been utilizing Dunn as a starting pitcher since selecting him in the first round of the 2016 draft.  He got off to a strong start at High-A last season (2.36 ERA over 45.2 IP), though he still owned a 1.27 WHIP.  Things really went downhill during his 15 start stint at Double-A, pitching to a 4.22 ERA and 1.36 WHIP as he struggled with his control (3.71 BB/9).  There’s no questioning his strikeout potential, but the control has often wavered and he also appears primed to struggle with home runs as he advances (career 1.03 GO/AO).  It will be interesting to see if he ultimately moves back to the bullpen, though there is upside as he continues to learn and develop.  He could emerge as a mid-rotation starter or become a lights out reliever in time.

7) Logan Gilbert – Right-Handed Pitcher (Grade – B-)
Gilbert didn’t pitch after being selected 14th overall in the 2018 draft.  Reports have him throwing four pitches, hitting the upper-90s with his fastball, and at 6’6” and 225 lbs. there is no question that he has the size to hold up to a starter’s workload.  It will be interesting to see how he fares once he actually steps on a professional mound, but with the size and repertoire it’s not unthinkable that the 21-year old moves quickly through the Seattle system.

8) Cal Raleigh – Catcher (Grade – C+)
A third round pick in 2018, Raleigh showed some potential at Low-A hitting .288 with 8 HR over 146 AB.  Obviously at 21-years old you can argue that he was too advanced for the level, but it was his first taste of professional baseball and an 8.9% SwStr% and 10.4% walk rate are promising.  The fact that he’s a switch hitter helps his appeal, the question is going to be whether or not he can stick behind the plate defensively.  If he can, the potential will be there to be an above average offensive catcher in the Majors.

9) Noelvi Marte – Shortstop (Grade – C+)
Signed out of the Dominican Republic, the 17-year old Marte has yet to make his professional debut.  Reports have the power potential as being for real, but he’s a long ways away and easily could outgrow the position (he’s currently listed at 6’1” and 181 lbs).  It will be interesting to see how he matures/develops, but he could make leaps up these rankings this year and join Julio Rodriguez in forming and intriguing young future core.

10) Erik Swanson – Right-Handed Pitcher (Grade – C)
The The numbers were impressive last season, with a 2.66 ERA and 1.00 WHIP across three levels (the bulk of which came at Triple-A, with 72.1 of his 121.1 IP there).  His deliver brings some of his success, helping to a 10.28 K/9 (courtesy of a 12.4% SwStr%), and he also has strong control (2.15 BB/9).  That said from a pure stuff perspective many feel he could ultimately be ticketed for the bullpen.


Dropped Off The Rankings
9) Sam Carlson – Right-Handed Pitcher (Grade – C)

Carlson is just the latest in the “risky” prospects filling out the Mariners system.  Selected in the second round of the 2018 draft, Carlson underwent Tommy John surgery in July and could ultimately miss all of 2019.  There is obvious upside (if healthy you could argue a B-/C+ grade), but there’s always risk that he doesn’t fully recover and that has to be factored into the grade.

10) Braden Bishop – Outfielder (Grade – C)
Now 25-years old, Bishop spent the year at Double-A hitting .284 with 8 HR and 5 SB.  The low stolen base number is a concern, since his speed is considered his best tool.  The potential is there to develop into a top of the order bat, with the potential to be a stolen base threat and his already solid approach (8.5% SwStr%, 9.4% walk rate).


Keep An Eye On
Matthew Festa – Right-Handed Pitcher (Grade – C)

Festa is a reliever who should get an opportunity in 2019 and quickly play a role as a late game option.  He racked up 20 saves at Double-A, showing elite swing and miss stuff (15.8% SwStr%), extremely good control (2.20 BB/9) and enough groundballs (46.0%).  While he’s not going to close immediately for the Mariners (Edwin Diaz and all), don’t be surprised if he starts getting talked up as a potential closer of the future.

Sources – Fangraphs, MLB.com, MILB.com, Baseball Reference

Order Rotoprofessor’s 2018 Fantasy Baseball Draft Guide for just $7.75!!  Click here for the details, but don’t miss out on the best bargain in fantasy baseball preparation.

Make sure to check out all of our 2019 Top 10 Prospect Lists:

AL EastAL CentralAL West
Baltimore OriolesChicago White SoxHouston Astros
Boston Red SoxCleveland IndiansLos Angeles Angels
New York YankeesDetroit TigersOakland A's
Tampa Bay RaysKansas City RoyalsSeattle Mariners
Toronto Blue JaysMinnesota TwinsTexas Rangers
NL EastNL CentralNL West
Atlanta BravesChicago CubsArizona Diamondbacks
Miami MarlinsCincinnati RedsColorado Rockies
New York MetsMilwaukee BrewersLos Angeles Dodgers
Philadelphia PhilliesPittsburgh PiratesSan Diego Padres
Washington NationalsSt. Louis CardinalsSan Francisco Giants

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