Johnny Cueto
During that fateful Cardinals-Reds fight in 2010, Reds pitcher Johnny Cueto was pinned against the wall behind home plate. His solution? Kick his way out. Cueto subsequently drilled Cardinals backup catcher Jason LaRue in the face with his cleat, giving LaRue a concussion. LaRue had dealt with several concussions before, and after the kick, LaRue was unable to be in a moving car or take care of himself.
According to LaRue, Cueto never reached out to apologize for his actions. LaRue had planned to retire after the season, so it wasn't a career cut short, but Cueto's actions linger in the minds of Cardinals fans, who were undoubtedly delighted when Pittsburgh Pirates fans rattled him in the 2013 National League Wild Card game.