Rick Fox: The Real World Was Too Much for Junior Seau

Junior Seau fell victim to a problem encountered by many former pro athletes -- post-career depression -- this according to former pro athlete-turned-actor Rick Fox.

Fox tells TMZ, retiring from a professional sport leads to a massive shift in lifestyle -- from glorified hero to relative anonymity -- and for some players, the change is too tough to handle.

Fox tells us, "At the end of the day [Junior] shot himself in the chest, which is the heart, and a lot of people die of a broken heart when they leave the game."