Teams interested in signing young amateur pitchers tend to look for clean deliveries and arm actions, guys who look like future starters. Perhaps that’s why some teams didn’t consider Herrera when the 2021 international signing period opened. The Rockies were willing to think outside the box and bring the smallish lefty with the funky mechanics into the organization; initial progress was slow. Herrera spent two years in the Dominican Summer League and one in the Arizona Complex League, but he started taking off in 2024, pitching his way from Single-A Fresno to High-A Spokane, where he finished things off with three perfect innings during the team’s championship run. He tacked on 10 strong appearances in the Dominican Winter League.
Used only as a reliever, Herrera relies largely on his fastball-slider combination to go right after hitters. His fastball sits around 95 mph and touches 97 and it comes from a low three-quarters arm slot, an upshoot heater that has carry above the barrel that gets a lot of swing-and-miss. He can get too fastball-reliant and will have to keep learning to trust his 84 mph slider. It's a pitch he has improved by more consistently staying on top of; it flashes better than average while dropping below barrels. He actually has feel for a changeup with depth, but he doesn’t throw it much.
Herrera pounded the strike zone during his time with Fresno, but he wasn’t as sharp with Spokane. He’s made adjustments before, so there’s confidence he’ll be able to become another legitimate big league bullpen piece for the Rockies.
