Top 10 Prospects (2020): Seattle Mariners: Some Intriguing Names, Especially At The Top, Give Hope


It’s no secret that the Mariners are in the midst of a deep rebuild, consistently trading away veterans for pieces to help in the future. You can argue that they haven’t always done well in those trades, but they have built up a system that has potential to produce at the highest level. Who are the names we should know? Who has the highest ceiling? Let’s take a look at the best that the Mariners’ system has to offer:

1) Jarred Kelenic – Outfielder
ETA – 2021
Grade –

Acquired as part of the Edwin Diaz/Robinson Cano blockbuster, Kelenic’s inclusion is the reason the Mets could ultimately regret the deal.  Playing across three levels (including 83 AB at Double-A) Kelenic hit .291 with 23 HR and 20 SB, including having added 31 doubles and 5 triples.  He was seen as having plus power potential when he was drafted, and while it was expected to take longer to develop it has already presented itself well at 20-years old.

He doesn’t have blazing speed and the SB could shrink as he matures physically, but he should remain a double-digit threat.  His approach, at his age, is solid with an overall 22.2% strikeout rate and 10.0% walk rate.  His SwStr% did rise as he advanced:

  • Single-A – 10.4%
  • High-A – 14.1%
  • Double-A – 11.6%

We’ll need to monitor the mark, though having improved going from High-A to Double-A was an important sign.  As long as he can keep the strikeouts in check, the other skills should make him a highly impressive player at the highest level.

2) Julio Rodriguez – Outfielder
ETA – 2022
Grade – B+

Rodriguez, who played all of 2019 at 19-years old, is already listed at 6’4” and 225 lbs., and he’s never going to be a big contributor on the bases (and ultimately he’ll likely settle into a corner outfield spot).  His power is for real, with 12 HR (as well as 26 doubles and 4 triples) over 367 PA across Single-A (263 AB) and High-A (65 AB).  The early results will bring some questions to his approach, with an overall 6.8% walk rate and a SwStr% that could be exposed further as he advances:

  • Single-A – 16.1%
  • High-A – 11.0%

Obviously we’d want to get excited that the number improved, especially at his age, though it was a small sample size so we can’t put much stock into it.  As long as he can keep that in check and we are talking about significant power with a solid average (though just a small cut behind Kelenic).

3) Logan Gilbert – Right-Handed Pitcher
ETA – 2020
Grade – B

The team’s first round pick in 2018, Gilbert pitched across three levels in 2019 (his first year on the field) and thrived with a 2.13 ERA and 0.95 WHIP over 135.0 IP.  He showed impressive strikeout stuff (11.00 K/9 courtesy of a 14.6% SwStr%) and excellent control (2.20 BB/9), but the question is going to be if home runs ultimately plague him.  Just look at the groundball rates by level:

  • Single-A (22.2 IP) – 22.5%
  • High-A (62.1 IP) – 45.0%
  • Double-A (50.0 IP) – 32.8%

It wasn’t an issue yet, but it seems inevitable.  His stuff and control make him an intriguing potential mid-rotation starter, though there are limitations to his ceiling.

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

White signed an extension in the offseason, which cleared his spot in the Opening Day lineup despite playing 2019 at Double-A (365 AB at the level in ’19).  There had been questions about his power potential, but he’s begun tapping into it as he’s developed (18 HR in ’19) and it should continue to grow.  However at what expense does that power come in terms of his approach?  Just look at the numbers:

  • Strikeout Rate – 23.0%
  • Walk Rate – 7.2%
  • SwStr% – 12.4%

He’ll turn 24-years old before the 2020 season ultimately gets underway, so it’s hard to anticipate a significant step forward in his development.  With the potential to be exposed as he continues to advance, keep that in mind before assuming he’s going to excel immediately.

5) Noelvi Marte – Shortstop
ETA – 2024
Grade – B-

When it comes to Marte it’s all about projection and upside, as he’s still just 18-years old.  Signed as an international free agent in 2018, and one of the best in the class, Marte showed both power (18 doubles, 4 triples, 9 HR) and speed (17 SB) while playing in the Dominican Summer League.  Obviously a lot can happen between now and when he arrives, but expectations are that he can produce across the board with power being his strongest asset to go along with a solid approach and some speed.  There’s enough upside that regardless of where he settles in defensively the potential impact makes him well worth monitoring.

The Next Five:

6) Justin Dunn – Right-Handed Pitcher (Grade – B-) – Another piece of the Diaz/Cano blockbuster, Dunn spent the year at Double-A and posted a 3.55 ERA and 1.19 WHIP over 131.2 IP.  A solid 12.3% SwStr% led to a 10.80 K/9 and 2.67 BB/9, though a 37.2% groundball rate indicates the potential for home run issues.  He’s already arrived in the Majors and should be an option for the team in 2020, though the real key will be whether or not his changeup can develop.  If it does he’ll be a solid mid-rotation starter with the potential for a little bit more.

7) Jake Fraley – Outfielder (Grade – B-) – Fraley went from Double-A (259 PA) to Triple-A (168 PA) and ultimately the Majors (41 PA).  While he struggled in his small MLB sample size (.150 with 0 HR), his production in the minors was highly impressive (.298 with 19 HR and 22 SB).  The Double-A production was buoyed by a bit of luck (.370 BABIP), which skews the results, but he did show an ability to make consistent contact (9.8% SwStr% in the minors).  There are questions about the power potential overall, but even as a 15/15 type player there would be upside appeal.

8) George Kirby – Right-Handed Pitcher (Grade – C+) – After being selected in the first round of the 2019 draft Kirby made his professional debut and promptly had 25 K vs. 0 BB over 23.0 IP.  That’s highly impressive, regardless of the level, even though you could argue that he was “old” for the level as a college pitcher.  Still he brings four pitches with above average control, giving him an intriguing floor of a solid starter (and the upside is to develop into more than that).

9) Cal Raleigh – Catcher (Grade – C+) – Raleigh split time between High-A (310 AB) and Double-A (145 AB), hitting .251 with 29 HR and 82 RBI.  There are going to be questions about his ability to make consistent contact (14.2% SwStr% overall, which leaped to 16.2% at Double-A).  There’s no questioning the power, which he put on full display in ’19, but if he can’t make consistent contact will it matter?  That makes you think that he’ll be the “prototypical” catcher, who hits for power and a poor average, though one that could play in the Majors.

10) Brandon Williamson – Left-Handed Pitcher (Grade – C+) – The team’s second round selection in 2019, Williamson was impressive in his first taste of professional baseball.  It was only 15.1 innings, so we have to keep that in perspective, but a 14.67 K/9 (courtesy of a 19.8% SwStr%), 2.93 BB/9 and 57.1% groundball rate is going to open up some eyes.  The actual repertoire may not be elite, but he’s left-handed with solid stuff and that’s going to lead to opportunities.

Source –,, Fangraphs

Make sure to check out all of our 2020 prospect rankings:

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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