Seattle Mariners Ranking 5 Potential Future Aces to Anchor Rotation

3. Justin Dunn

Finally, we get to an in house option. You might be surprised to not see Yusei Kikuchi or Justus Sheffield here, but I don’t think either guy has much of a chance at ace status. That isn’t to say they can’t be really good, even great pitchers. But I think there are legitimate command issues with Sheffield, and Kikuchi just doesn’t have the raw stuff to be an ace. Both are probably solid #3’s.

I put Dunn ahead of those 2 in particular because he still has room to grow. Kikuchi and Sheffield are at the stage where they can make minor adjustments to maximize value. Dunn is still raw enough to have a significant change in his profile.

The mid-90s fastball and sharp slider already give him a great shot to be a top of the rotation option. The curveball and changeup have both shown more promise of late and Dunn is a great athlete who can refine his command even more.

He is off to a great start in the organization, posting a 1.88 ERA with 21 strikeouts in 14.1 innings with 5 walks and a .196 opponents batting average. Seattle will have to fight the urge to move Dunn to the bullpen where his stuff could play up more and can be a premier high-leverage option.

The urge shouldn’t be too difficult since 2019 is a refocusing year anyways. Seattle will let the youngster develop as a starter, knowing that the bullpen option will always be available to them. Dunn has the raw goods, athleticism, and enough helium to make the jump from mid-rotation arm to ace if things break right. He only needs time to get there.