SF Giants top prospects: No. 26 — RHP Kervin Castro
Highest Level: Low-A (Salem-Keizer)
Acquired: IFA (2015)
Future-Value Grade: 40
A breakout performance at instructs last fall quickly shot Kervin Castro and Gregory Santos up my rankings. Both showed significant jumps in velocity alongside more consistency from simplifying their arsenals. Both were in the conversation to be 40+ to 45-grade prospects heading into, what I believed, would be their final chance to prove they could be big-league starters. Instead, the Giants appear to have already decided to convert them to relievers.
Even before his jump last year, Castro was the ace of the Salem-Keizer Volcanoes, posting a 2.66 ERA across 14 starts with 61 strikeouts and just 13 walks across 67.2 innings of work. Primed to start 2020 at Augusta or San Jose, fans will be left wondering if he (or Santos) were on the cusp of becoming premium starting pitching prospects in 2020 before the pandemic took that opportunity from them.
That counterfactual should not distract Giants fans from Castro’s elite high-leverage upside. He already showed strong control as a starter and consistently held his own against older competition. His fastball now sits in the mid-90s and occasionally reaches 97 and 98 mph, but his curveball has taken an even larger step forward since shifting to shorter outings. His once loopy breaking ball has become more refined with sharper downward movement and now routinely looks like a plus offering. Assuming he maintains his jump in velocity, he should have two above-average or better pitches.
I would have been slower to move Castro out of the rotation, but the Giants have been open to unique deployments. Perhaps they view Castro in a unique hybrid role, which would lead his grade to tick up to 40+. Otherwise, he still projects to be a strong middle reliever with a chance to turn into a high-leverage option.