Rooney hip injury nonsense

I don't get it? Can someone explain it to me? If the idea of playing the team we did against Chelsea was to rest players for Barca then why are we now left with a potentially injured rooney? He took a knock against Blackburn and it's obviously been aggravated against chelsea. He should have been the first player on the list for a "rest" if he was carrying a slight knock. Am I missing a trick? Would it not have been better to put out a virtual second team and tell them to go out and attack chelsea and see what happens?
Fergie to me is showing signs of neither doing one thing or another. He says we must impose our game on barca at the Camp but then we go into our shell. He says we need to rest players but then rooney plays (who was surely the one player who had a definite knock) Isn't this the managerial equivalent of a "cross- come -shot" that is neither a cross nor a shot and ends up just being a waste of an opportunity? It has that feel about it for me. I think he's caught between two goals (CL + PREM) and wants to attack but can't bring himself to do it. He wants to rest players but then doesn't rest the right ones. There's an old buddhist phrase - "Man who chases two rabbits catches neither"