You're seeing it now more than ever. Players suddenly collapsing with a "leg injury" to slow down opponent momentum or get a free timeout. And it's getting worse and worse. There were a couple games yesterday that seemed to have these every drive. IMHO there needs to be some kind of non-yardage penalty. For example, any player who falls to the ground with injury should have to miss the remainder of the quarter (or maybe even half) before he can re-enter.