If you play someone who is at less than 100%, is there a negative impact on their performance, or only an increased likelihood that they will be more seriously injured?

My understanding is that the percentage is used as a multiplier for the player's ratings to determine their "performance while injured" for a particular game.

So if a player has a Perimeter rating of 100, but is at 85 due to injury, then his perimeter rating for that game effectively is 85 (100 x .85).

At least that's how I've always handled matters when determining whether or not an injury is significant enough to warrant juggling my starting lineup/playing time in a given game.

The notion of it being a direct multiplier effect is realy conjecture. It may or may not be accurate, but I'm pretty sure that it's more of a forum fact than a confirmed fact.

I think the total number of injuries is down, but there are more severe injuries than before

It has been number of seasons, but I had an injured player that was taking his time recovering.  I was going to rest him until he was at 95%.  His WE started to drop.  I sent a ticket the the responce I received was "If a player is 80% or above why wouldn't you play him?  He will lose WE if he is 80% or better health and not playing."  So that is the rule I now live by.

That's interesting. My last injured player was 3 seasons ago. He was a 9 Dur. His health went to around 50 and I was going to let him sit to 95 as well, but the same thing happened with his WE. I thought it was a function of how long he was hurt. I'll take note of the feedback. Thanks.