At 19, Bruce Sutter woke from arm surgery to find the velocity that got him signed was gone, and his career seemingly dead. This deep dive traces how that catastrophic breakdown became the prerequisite for a historic career, as a pitcher who physically could not throw normally stumbled into a revolutionary pitch and redefined the bullpen closer.

A multi-sport prodigy from Lancaster, Pennsylvania, Sutter learned a modified forkball, the split-finger fastball, from instructor Fred Martin, exploiting his naturally massive hands. The pitch dropped as if gravity took over, and it made him the first pitcher inducted into the Hall of Fame without ever starting a major league game, while forcing managers to reshape how they used their rosters.

• In 1977 he threw an immaculate inning, striking out three Expos on nine pitches, statistically  ...