“Sodo Mojo Presents” Top 30 Mariners Prospects #1 Justus Sheffield

We have finally arrived at the number 1 spot on our countdown of the Top 30 Seattle Mariners Prospect list. Who’s number 1? Well, you probably saw this coming from a mile away.

As always, for a breakdown of our process in selecting the Top 30 Mariners prospects, read the primer by clicking here. If you want a breakdown of our first 29 prospects, you can go to the “minors” tab on the website, or click right here.

In addition, remember that our grades are based on the standard scouting scale. The scale ranges from 20-80, 20 being not MLB quality and 80 being a Hall of Fame tool. We also provide a probability score on a 1-5 scale, based on the likelihood they reach the 75% plateau of their upside. With all that in mind, let’s get started.

1. Justus Sheffield

Yes, the number 1 spot on our Top Prospect list belongs to the near consensus top prospect on other Mariners list, LHP Justus Sheffield. The centerpiece of the James Paxton trade, there is immense pressure on Sheffield to perform.

The Mariners look at Justus Sheffield and see a potential #2 starter. He already has 2 plus pitches, including a fastball that can sit in the mid-90’s, but has more life and command when sitting at 92-93 mph.

Sheffield’s slider is the pitch that gives him a shot to be special. It is a two-plane pitch that he controls well. The sweeping slider will wreak havoc on lefties and can be used to get the back-door strike against right-handed.

The question for Sheffield has always been his 3rd pitch. He has a mediocre at best curveball and a changeup. The changeup is his best shot at a 3rd quality offering and Sheffield knows it. He spent all off-season working on the pitch and the early returns have been exciting:

That changeup shown is a plus offering. While we will need to see it with more consistency before grading it as a plus, all the tools are there. He throws the pitch with good arm action and deception.

There were some concerns that Sheffield’s size could hinder his endurance, but there is no evidence to suggest Sheffield cannot be the 180 innings pitched type of arm. At 6’0″, 205 lbs, Sheffield is a good athlete who repeats his delivery well with clean arm action. He is only 22-years-old, so he has yet to reach his peak physical condition, suggesting there may be more in the tank than he has shown.

Sheffield will likely start the year in AAA Tacoma but could be amongst the first called up to take a start should one of the projected 5 need to skip a start. He is ready right now, but the Mariners will likely send Sheffield to work on his command, changeup, and to push back his service clock.

Scouting Grades- Fastball: 60 Slider: 65: Curveball: 40 Changeup: 50 Command: 50 Probability: 4/5

Now the reason Sheffield edged out Kelenic for the number 1 spot is the probability. Sheffield’s proximity to the big leagues and success in the high minors make him a better bet to have MLB success than Kelenic.

Obviously, both prospects have excellent chances to become MLB contributors and both have All-Star potential. For the first time in a long time, there is some legitimate debate over who the best prospect in the system is. And now, that debate isn’t over some potential #4 starter or a 2 win regular. Now, the debate is over players with massive upside and potential to turn around the Mariners for the better part of the next decade.