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

The Cactus League season is underway and the Mariners young players are playing quite well. But we continue to move along, unveiling our Top 40 Mariners prospects 5 at a time.

Today, we continue our official countdown, revealing the next 5 prospects to crack our Top 40 list. As we move up the list, more or more names will be familiar to Mariners fans. And now, we are officially inside the Top 10 with a large number of these names figuring to get to Seattle in 2020.

But before we do, let’s review our process. First, the rankers consisted of 4 staff writers. All 4 writers produced a list of their top prospects. The average rank of each player is the spot they landed on our list. In this case, the lower the number, the higher the rank.

Our rankers were not given any criteria for their list. Different eyes see different things and unique minds value things differently than others. There are no cookie cutters for prospect scouting and beauty is in the eye of the beholder.

Also, take these ranks with a grain of salt. We do not get to see many of these players often and are relying on graining video, scouting reports, and statistics to cover our bases. If you want top-end prospect ranks, I suggest Keith Law of ESPN as well as Eric Longenhagen and Kiley McDaniel. So, let’s get started.

Isaiah Campbell is the 2019 third-round selection whose large college workload stopped him from making his pro debut in 2019. Campbell won’t have any such restrictions this year and will likely head off to West Virginia to start his season.

Campbell has a good arsenal including a 91-95 MPH that can hit 98 MPH in short stints. He has a 60-grade slider that shows up to 70-grade on occasion. The fastball/slider combination alone makes him a high-leverage reliever and possible closer in the future. This high floor will get lazy scouts to call him reliever right now, but there is absolutely no reason to move him out of the rotation right now.

Campbell has two more pitches, including a solid-average split-changeup that could settle into another above-average offering for Campbell. The curveball is fringe-average at best, but has a shot to get to average, which could give Campbell 4-pitches that are average or better, including a plus slider.

Campbell throws strikes and has above-average control. But his command hovers closer to 50-grade than 55-grade, but Campbell is a good athlete with relatively clean mechanics, so both could improve a half-grade or more.

Campbell has a higher-floor than most, but also has a chance to be a #2 starter. But the path to get there is more difficult than other arms on this list, which is why he comes in at 10. With a solid pro debut, Campbell could climb into the Top 5 in our initial 2021 ranks.

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.