No. I never played football.

I enjoy watching the game of football.  I don't understand all the rules,  plays and positions,  but I know enough to understand many plays and the goal of the game.  What I don't understand though, is why a player would go into a game with a large knee brace on and perhaps more importantly, why his coach would not only allow it, but seemingly encourage it?  Do they not understand this is NOT a good thing?  Not only would he not play as well but odds of re-injury are, I assume greatly increased.  If this coach is paid for his expertise and good judgement, is he and I'm  assuming here, overpaid?............marge    P.S.  AND...I've been told the player needed permission from the team doctor and  got it.  YES.  He did re-injure his knee and apparently IS facing surgery.............marge