Rooney ruled out of Blackburn clash
The striker, whose 34 goals have underpinned United's title challenge, lasted 55 minutes against Bayern after making a surprise return to action just a week after damaging ankle ligaments in the first leg.
"I don't think it's as serious as we said the first time, but I think he'll be ready for the (Manchester) City game," manager Alex Ferguson said on Friday.
"We've got more time to work on it, anyway. Other than that everyone else is fit."
United, who went out of the Champions League on away goals after the tie ended 4-4, are two points behind leaders Chelsea with five matches remaining.
Rooney was missing when United were beaten 2-1 at home by Chelsea last weekend.