Booing is classless but there should be a rule that if you go down you sit out two serious after you go down or even a full quarter. I mean if you want to side on player safety that will help with player safety.Players are coached to go to the ground whenever they are injured so that the team has time to get their backup into the game. There isn't a single fan in the stands who has any clue whether or not a player is actually injured. The timing was poor, no doubt about that, but it doesn't change the fact that booing an injured player is classless.