The Astros' trade of Jarred Cosart cleared a spot in their rotation, which will be filled by Brad Peacock. But it also opened up a spot on the 40-man roster that was filled by the promotion of Mike Foltynewicz to fill a role in the bullpen.
Foltynewicz has been considered the Astros' best starting pitching prospect, but this will give him a chance to get acclimated to the big leagues in an easier role. There are scouts who have projected Foltynewicz as a reliever long term, but for now, this appears to be a short-term move, not a permanent switch.
Foltynewicz has some of the best pure velocity in the minors. He sits at 95-97 mph as a starter and has regularly tickled triple digits. His fastball can be too straight at times, especially when he's up in the zone, but when he gets it down in the zone it shows some sink. If he can locate it down in the zone early in the count, he can then elevate late in the count for strikeouts. His secondary stuff is still a work in progress. Foltynewicz's breaking ball is still too slurvy even after a switch to a spike curveball, generally lacking the bite that he flashes occasionally. His changeup has improved this year as he maintains his arm speed more often, but it's still a below-average pitch.
Pitching out of the bullpen, Foltynewicz will be able to largely scrap the changeup and focus on the fastball/breaking ball. With the added velocity bump that comes from shorter stints, that should be enough to get big league hitters out.
WHAT TO EXPECT
In a relief role, Foltynewicz should pick up strikeouts, but his below-average command means he'll also allow too many walks and may post average at best WHIPs. Long-term, he's too valuable to the Astros as a starting pitcher to stick in this role long-term, as he still has at least a chance at a front-line starter role with continued refinement.