Of course it's not up to the players when they are questionable on the injury report. It's up to the training staff and the coaches whether they play or not. I'm sure it's a balancing act weighing having the player to help contribute now and risking further injury vs. allowing the player to rest/heal and having them for the longer run. I would guess most players lobby to get back as quickly as they can, but they don't always know what is best for themselves.