Justin Morneau

Before the concussion, Morneau was a legitimate middle-of-the-order force for the Twins, combining gap power with solid contact skills. His 2006 MVP season showcased a player hitting .321 with elite run production. After 2010, he never again posted an OPS+ above 110, managing just 65 home runs over his final six seasons.

Morneau's tale serves as a sobering reminder of how quickly careers can change. He finished with respectable counting stats — 247 homers and 985 RBI — but those numbers only hint at what might have been without that fateful collision at home plate.