Former defensive tackle Christian Ballard says there is no deep, dark secret about why he abruptly left the Minnesota Vikings during training camp. He's not mentally or physically ill.

Christian Ballard walked away from the Minnesota Vikings and the NFL. (Charlie Neibergall / Associated Press) By Houston Mitchell . Sept. 18, 2013 8:04 AM PT . Share via Close extra sharing options.

Two former NFL players, Christian Ballard and Gregory Westbrooks, filed a lawsuit Thursday alleging the NFLPA withheld information about the perils of head injuries. The suit, which names former ...