The Mariners' pitching lab works wonders with bullpen guys. They transformed Edwin Diaz from a middling starter into an elite closer. The same group took a shot on a back-end starter and turned him into one of the most dependable closers in the game (Paul Sewald). This year they took on their next task, converting Prelander Berroa from an electric arm with a penchant for free passes into one of the most dominating relievers in minor league baseball. Mission accomplished!
Berroa, our 16th-rated prospect, switched to the bullpen after five uneven starts with the Arkansas Travelers. He would relieve in 38 games (59 innings), striking out 92 batters. The most significant development is the walks shrunk a la Matt Brash, making the Mariners look like geniuses again. While the decrease in walks is a feather in Berroa's cap, the arsenal is where he makes a living.
The 23-year-old reliever routinely hits triple digits with his heater, which offers arm-side run. He tends to get whiffs and groundouts from his slider, and he even has a changeup to neutralize lefty bats. Berroa showcased that arsenal in his major league debut this summer.
Berroa carved up Texas League hitters in 2023 thanks to the Mariners development staff seeing a familiar profile (Diaz, Brash) that could excel in shorter stints. There is a good chance he will flash in Peoria this spring and leave Spring Training with the big club. It will all come down to the command and control. Imagining a late inning scenario where Scott Servais rolls out Berroa, Topa, Brash, and Munoz sounds awfully nice.