Guerra has been on this list before, but not in this capacity. When the Padres landed him from Boston in the 2015 Craig Kimbrel deal, Guerra was widely regarded as one of the top shortstop prospects in the sport. He would develop into one of the Minor Leagues’ best defenders (with a cannon for an arm). But his bat never came around. Guerra slashed just .237/.290/.374 across seven Minor League seasons. So the Padres hatched a plan.
They began converting Guerra into a right-handed reliever in spring of 2019, and it paid dividends instantly. Guerra’s delivery was smooth, and his fastball hit triple digits while sitting in the high 90s. On top of that, Guerra seemed to pick up the habits of a pitcher quickly. His delivery was easy and repeatable, with an arm slot just above three-quarters. His fastball had arm-side run, and his slider serious potential, though it needs to be harnessed.
Guerra posted a 3.38 ERA in his first Minor League season as a pitcher, striking out 12.7 hitters per nine innings. His pitching debut was so impressive that Guerra was promoted to the Padres in September. After a years-long struggle to break through at shortstop, Guerra suddenly has the long-term ceiling of a high-octane bullpen weapon. The Padres clearly believe in that ceiling.