David Peterson wasn’t really on anyone’s draft radar until about midway through the 2017 college season. From out of nowhere, he showed up due to an impressive strikeout to walk ratio (140 to 15) and became the University of Oregon’s Friday starter. I did have the privilege of watching him pitch in person and at times he was flat out unhittable for a U of A team that reached the NCAA tournament. However, he doesn’t have a lot of MLB upside in terms of top of the rotation ability.
Peterson throws the full mix, but only his fastball and slider are mostly developed. He’s going to have to improve the change-up in the minors. His curveball is basically a get-me-over pitch that he uses to steal strikes, but he doesn’t need it to be successful. At 6’6” 240, he’s fully filled out but there is still a lot of projection in his development. Because of that issue and being older than your typical HS pitcher by 3 years, he’s going to be picked somewhere between the teens and the top of the 2nd round since there is a good chance he doesn’t reach the majors before his 25th birthday.
Fastball: Peterson uses his height and length very well and throws the ball on a downward plane with arm-side action. The pitch sits in the low 90s and can reach for mid 90s. The heavy action on the ball should make for a very good ground ball pitch if he can command it down in the strike zone. Grade: 55/65
Curveball: As I said before, it’s a get-me-over pitch with very little other purpose. He could develop that in the minors, but that adds to development time. I think he should table the pitch altogether if he wants to minimize the amount of time to develop since the slider and the change-up should be enough. If the change-up doesn’t develop, he can take the Robbie Ray approach and go back to it later. Grade: 40/45
Slider: This is Peterson’s go-to breaking ball. It’s a pitch that is still inconsistent, but will flash above average to plus at times. The pitch sits in the mid 80s and gets some lateral action on it. For Peterson to succeed in the majors, this pitch has to be consistent for him. Grade: 45/55
Change-Up: Peterson shows the ability to change speeds effectively, although the change-up needs more fade to it to match the action of his fastball. The change is another pitch that needs a lot of development, because it could be the difference between a middle of the rotation starter and a bullpen arm. Grade: 45/50
Command: Peterson is not afraid to attack the strike zone and that is simultaneously his greatest strength and weakness. He is aggressive in the zone and looking to always jump ahead in the count, but he seems to prioritize strikes over quality strikes. As he develops, hitters in the pros will attack his first pitch strikes more aggressively and that could lead to him giving up a ton of hits and runs. If he can continually focus on commanding the ball towards the edges of the zone more, I think he’ll be fine. Grade: 55/60
Overall, I think there isn’t enough floor for the Diamondbacks to justify picking him at 7 with better options in the position player pool already for under-slot picks and pitchers in the 7-15 range. If you compare him with Alex Faedo, there isn’t any debate who the Dbacks should pick at 7. Peterson has made some significant strides in simplifying his delivery and mechanics as a junior, but he is under-developed compared to some of his piers in the draft.