SF Giants top prospects: No. 21 — RHP Trevor McDonald
Highest Level: Rookie (AZL)
Acquired: Draft (2019)
Future-Value Grade: 40
Trevor McDonald was projected as a third to fifth-round prospect by most rankings leading up to the 2019 draft. Generally speaking, prep pitchers tend to have the widest variation in opinions. It’s not shocking to see a player get drafted towards the end of Day 1 with those rankings. When he wasn’t selected in the first ten rounds of the draft though, many assumed he was going to honor his commitment to South Alabama.
Instead, due to MLB’s complicated draft spending rules, the Giants finagled their spending to sign him for an $800,000 bonus, equivalent to the slot-value of a late-Day 1 selection.
McDonald first made waves by striking out 88 batters and posting a 1.49 ERA during his junior year in high school. Still, he was considered a top recruit more than a premium pro prospect.
That offseason, he made a bold decision to try and take a step forward. McDonald took a break from pitching and focused on bulking up his scrawny frame. It showed pretty quick results. After adding 20 pounds, his fastball held 91-93 mph throughout most of his starts while touching 95 mph as a senior.
On its face, a low-90s fastball isn’t particularly noteworthy. However, McDonald had already shown advanced pitchability and feel for a breaking ball that has the potential to be a 60-grade pitch. McDonald also works from an unorthodox delivery that adds deception and helps his velocity play up, according to one industry source.
At the same time, his delivery is the source of some scouts concern. Many believe McDonald’s motion has too many moving parts to stick in the rotation. While it isn’t how you’d draw it up, Giants officials are confident that McDonald has shown enough consistency to make it work.
He still needs to make a lot of progress with his changeup. It’s unlikely it’ll be able to develop into much more than a 45-grade pitch, but his other stuff is good enough to make it work.
Due to the draft bonus finagling, McDonald had to wait longer than most other prospects to sign last year. That meant his debut in the AZL came later and only lasted three appearances. He was quite impressive, but it’s hard to read much into it.
Prospects with the shortest track records are the hardest to gauge without a minor-league season. Still, McDonald has the tools to be a mid-rotation starter. If his velo regresses or changeup fails to develop, he should be a solid long-relief option as well.