@baseballamerica: Kenny Serwa's knuckleball 😵💫 Serwa is a 29-year-old righthander in the Detroit Tigers organization who wields two variants of knuckle balls — a 78-82 mph "Yoshi" knuckle with dramatic movement and a power knuckleball that tops in at 88 mph. Serwa currently pitches for the Tigers' Double-A affiliate, the Erie SeaWolves. For more MLB prospect coverage, follow and subscribe to Baseball America.