Lebron is fortunate to have a mostly injury-free career so far. I don't know how he would bear a sever sprain or a dislocated finger. I hope I don't sound like a Kobe homer, but come on .. the guy has played with disclocated/broken fingers, with sprains, back problems and so on, even during regular season games. Lebron couldn't play through it in the most important time of the season and possibly his career.
I don't have any doubt that Lebron will bounce back and shut all the doubters up, but stuff like this really hurts his legacy. He may be a freak athlete, but he's no where near as tough as Jordan and Kobe.