Simpson at 6-foot-3, 220 pounds, was a big, hard thrower, but his minor league seasons were plagued by wildness.

[2] He began the year by winning 13 of his first 14 decisions (the loss came when a dropped pop fly allowed two unearned runs), including tossing a one-hitter, a two-hitter, and a three-hitter, in helping the Reds to a 70–30 start.

Simpson was the only rookie pitcher selected for the 1970 Major League Baseball All-Star Game, though he didn't pitch.

Simpson's injury predated, by several years, the early examples of rotator cuff surgery, the progress of which has helped at least some major league pitchers effectively recover from such a setback.

Simpson finished his career in Mexico, where he developed thoracic outlet syndrome, which threatened him with the loss of his pitching arm and even his life.