Touted by some as a future Hall of Famer, his career was permanently altered on April 8, 1984, when he was hit in the face by Mike Torrez's fastball. The pitch broke the orbital bone around his left eye and ended his 1984 season. He returned in 1985, but suffered from problems with depth perception that permanently hampered his potential. In 1991, Thon received the Tony Conigliaro Award in recognition of his recovery from this severe injury.
Thon is a third-generation baseball player. He is the grandson of Freddie Thon Sr., a native Puerto Rican who played and managed in the Puerto Rican Baseball League during World War II. His father Freddie Thon Jr., who signed a major-league contract but injured his arm before reporting to training, played semi-pro baseball while finishing college at Notre Dame, and coached all of his sons throughout their Little League and teenage years. Dickie's brother Frankie Thon is also affiliated with major league baseball in both the U.S. and Puerto Rico having been a player, a manager and a current major-league scout, as well as the general manager of the Criollos de Caguas in the Puerto Rican League.