Acosta signed with the Mets for just $70K in 2016. The 20-year-old has been stateside for two seasons, pitching in the GCL in 2017 and heading to the Appalachian League last summer. He projects better in relief long-term, and I saw him pitching short stints during my trip through Florida Extended Spring Training this year.
An extra-wiry 6-foot-2, Acosta will never be physical but has a bit more room to add muscle through his upper-half. He pitches exclusively from the stretch, with a long arm-circle that shows in the back leading into a whippy 3/4 slot. His lively fastball ranges between 91 and 95 mph, showing occasional run and late hop that hints a few more ticks of velocity are coming. His slurvy 78-to-82 mph breaking ball was inconsistent, a loose spinner that stayed up at times but showed better action as he got settled later in the outing. A firm changeup at 85-to-88 mph flashes vertical action at times, though he’ll need to take more off it in order to develop the pitch into an effective third speed.
Acosta will turn 21 before the 2019 season is over, making him on the older end for a prospect in Extended Spring Training. There’s not enough stuff or track record of performance to place in the FV 40 tier right now, though Acosta is a solid 35+ Follow type that could move up with an uptick in velocity from the bullpen.