SF Giants Top 31 Prospect Rankings: 2020 Midyear Update
SF Giants top prospects: No. 14 — RHP Blake Rivera
Highest Level: Class-A (Augusta)
Acquired: Draft (2018)
Future-Value Grade: 40+
I originally had Rivera slotted behind Jake Wong, but after talking to a source familiar with the Giants system, I bumped him up. Rivera has big-time stuff that is nearly ready to play in the back of a big-league bullpen, but Giants brass is confident he can stick as a starter.
His control and command have been spotty (4.81 BB/9 in 2019), but scouts see Rivera’s repeatable delivery and athletic frame (6’4”-225 lbs.) as signs of better consistency to come. If it does, he has one of the highest ceilings of any starter in the system.
Rivera’s best and most consistent pitch is his 12-6 curveball. Scouts are split on whether it projects as an above-average or plus pitch. Reports are the pitch has premium spin-rate and sharp downward break that suggests plus is attainable. His changeup oscillates wildly from a virtually unthrowable pitch to a secondary that could be an average big-league offering.
Ultimately how well Rivera harnesses his secondary pitches will determine whether he can stick in the rotation. If he can, how well his fastball plays will determine what his ceiling is. Rivera’s fastball can sit from 94-96 mph and touch 98 mph. That velocity combined with effective cut and a high 2600 RPM spin-rate allows it to play up as a potential 65-grade pitch.
At the moment, Rivera struggles to hold his velocity deep into games, often sitting in the low-90s. His fastball would still project as an above-average pitch, but if he doesn’t find a way to generate more consistent premium velocity his ceiling is probably more as a 4 starter. Corraling consistent premium velocity would move that window to a strong mid-rotation and maybe even fringe 2 starter.