Sodo Mojo’s Top 40 Seattle Mariners Prospects: 10-6

Next up on our list is the potential “catcher of the future” for the Mariners, Cal Raleigh. Raleigh actually tied with our #8 prospect, but you guys broke our tie, landing Raleigh at spot #9. Raleigh had a big 2019, slugging 29 home runs in his first full season of pro ball.

Raleigh was simply too good for High-A Modesto and when Logan Gilbert got called up to AA Arkansas, Seattle decided to keep his partner in crime together. Raleigh has vastly improved his defense behind the plate and now is earning solid-average defensive grades.

Raleigh’s best tool is still his power and depending on the ball he gets to hit in the future, a 25-30 home runs season isn’t out of the question. The biggest question remaining for Raleigh is his hit tool. The switch-hitter’s gameplan and approach are geared to take advantage of his power, but he’ll need to make more improvements going forward.

Raleigh needs to make more consistent contact to reach his ceiling. As a switch-hitting catcher with at least passable defense and plus power, Raleigh could be a multi-year All-Star.

Raleigh will start 2020 in AA Arkansas and will have a chance to make his big league debut late in 2020. An above-average bat and passable glove from a catcher is rare and Raleigh has a pretty good shot to get there. Mariners fans could be talking about him breaking with the team in 2021, but if he can’t improve his contact rates, it could take until 2022.

Justus Sheffield is a personal favorite of mine but a lot of people are down on the athletic lefty. This is largely based on his terrible tenure in Tacoma to start the year, but Sheffield righted the ship in AA.

When he has his best stuff, Sheffield’s arsenal includes a fastball 91-94 MPH with good life up in the zone. Sheffield’s best offering is his two-plane slider that can earn 65-grades on any given night. The changeup is a work in progress but flashes average with good arm speed and fade.

Sheffield has a pretty good chance at 3 above-average offerings, but whether or not he can harness those pitches will tell his story. Sheffield shows moments of 55-grade command, but mostly has issues commanding his fastball.

The fastball doesn’t have the velocity to play without command. If Sheffield can gain that skill, he has #3 stuff with athleticism to match. He shows above-average command of his slider and changeup, which may be a good sign for Sheffield’s long-term success with the fastball.

One of the skills Sheffield has shown is his ability to produce ground balls, a skill that shouldn’t be overlooked in the current offensive environment. Sheffield can get swings-and-misses with his slider, generating above-average whiff rates.

2020 will be a big year for Sheffield. He will have the entire season to show what his future with the ballclub can hold, with very little pressure to perform right away. Getting to 160 quality big league innings would be a big step for the 24-year-old in his first full MLB season. With his current command and stuff, a season with a low-4.0 ERA and about a strikeout per inning isn’t out of the question.

Justin Dunn is a little behind Justus Sheffield but should get an extended look with the Mariners at some point in 2020. Like Sheffield, Dunn has a high-leverage reliever floor, but with no expectations to win in 2020, Dunn will get every chance to show he can stick in the rotation.

Dunn has a slightly higher upside than Sheffield, but a better chance to wind up in the bullpen, hence his ranking similar to Sheffield. Dunn is a good athlete with a 92-95 MPH that hits 96 when pitching in the rotation. As a closer at Boston College, Dunn would hit 98 MPH, but since becoming a pro, he has operated in the mid-90s.

Dunn backs up his fastball with an above-average slider that flashes plus. Dunn also has a changeup that is fringe-average at times but lacks the upside or probability of Sheffield’s, giving him a bigger chance to end up in the bullpen.

Dunn throws strikes but is more control than command, another thing he will need to straighten out to stick in the rotation. If the Mariners do decide to move Dunn to the pen, he can ditch the changeup, speed up his delivery, and pump up the heater to the upper-90s and ratchet up the slider another half grade or so.

Dunn could wind up as a #3 or #4 starter. Or he could end up as the Mariners closer in 2021 or 2022. Dunn is going to be valuable for Seattle in some capacity. Whether it be in the rotation, out of the bullpen, or as a trade chip, Dunn will be an important player in the rebuild.

To wrap up this grouping, we have the potential number 1 prospect in the system this time next year. Noelvi Marte has a chance to make the meteoric rise similar to Julio Rodriguez did last year. Marte has a loud toolset that is easy to dream on.

Marte has a rare combination of plus raw power and plus speed and a chance to stick at shortstop. Marte has 70-grade speed and 60-grade raw power. Marte has a strong arm and is a great athlete. He is still learning how to play defense, and while he may not be able to stick at shortstop, he has the speed to play centerfield and the arm to handle third if needed.

Marte has the power to be a 25 home run and a 30-40 steal player. The hit tool has some work, but Marte has a lighting fast swing and good plate coverage, along with a sound lower body to provide power and balance.

Like many teenagers, Marte’s approach at the plate is raw and he sometimes struggles to read spin out of the pitcher’s hand. Identifying breaking stuff is an essential skill for big league success. But at just 18-years-old, Marte has already shown growth in the area and has plenty of time to improve.

Marte is still a young hitter who doesn’t have the natural hit tool that Julio Rodriguez did. But Marte will get his chance to make his stateside debut in 2020. Expecting Marte to progress as quickly as Rodriguez is too much to ask of any 18-year-old, but Marte has that chance.

Well, there you have it, our first 35 names are now off the board. Next time, we finally get to our Top 5 Mariners prospects. The talent thus far has been great. But the Top 5 has some serious upside to drool about.