How large is too large for football?

The NFL has some large players, particularly on the offensive line where it seems like all the linemen are at least 6’3″ and 300 pounds.The game has evolved from one with fairly normal people to one where players have to be behemoths or physical specimens at each position.

Mississippi walk-on lineman Terrell Brown is even bigger: 6’11” and 390 pounds. This is huge, massive. A couple thoughts:

1. Can one even be a good football player at this size? I imagine if he locked up with a defensive player, Brown could win on size alone. But how difficult is it to move all that weight? I could imagine some smaller defense players could make it difficult as they run around him.

2. Can one remain healthy while playing at this size? Linemen take a beating and it seems like tall athletes, like Yao Ming, have special issues.

3. What will his future life be like if football doesn’t work out? Offensive linemen bulk up quite a bit to play football but this is not the weight one would want to stay at for a lifetime.

Brown has a long way to go before these questions are answered – he is just a walk-on who apparently played at a community college and is not listed on recruiting sites. I’d be curious to see how his football future plays out.