I really would do it. During Cedar/Paradise fires of 2003, I played in a flag football game because the teams had already showed up and we thought, "Well, we might as well play." I totally regretted it. I felt like crap for an entire week. I don't know about long term damage, but you might end up being uncomfortable for a week, which isn't worth it.

EDIT: GAH! I mean, I really would NOT do it.