Basketball is a game of inches, and because of that, the difference between "injured-Ray" and the old Ray is MASSIVE.
On defense, that half-a-step difference in quickness is what made the old Ray passable on defense, whereas the new Ray looks like a revolving door. I saw the sixers go at him literally 3 possessions in a row, and each possession ended up in a bucket if I remembered correctly.
On offense, it's the difference between him coming around a screen and firing away a shot he usually makes, and what's happening now (he's comes around the screen too slow and his man is on him, so he can't even attempt to shoot and ends up just wasting the shot clock). Not only that, it's the difference between him having an all-time great jumpshot, and no jumpshot at all!
Playing Ray injured is, in reality, worse than just about any bench shooting guard in the league. He should be getting 10 minutes a night, if anything.
But alas, Doc is too stubborn when it comes to his vets, and it's a little late to start experimenting with other lineups now.