Wayne Rooney will miss Manchester United's game against Bolton on Saturday due to a calf strain, while the club are waiting to hear if Dimitar Berbatov will be available.
The England striker has picked up a minor knock and will not be risked at Old Trafford, although he could feature in United's midweek UEFA Champions League game at CSKA Moscow.
"Calf injuries can be troublesome," said United boss Sir Alex Ferguson.
"We are trying our best to get him fit for Wednesday but I have my doubts on that. But Wayne should be fit for the Liverpool game.
"We know how difficult these things can be so we will not be taking any chances with the Moscow trip."
Ferguson's striker conundrum is further exacerbated by Berbatov's possible absence due to his girlfriend giving birth in midweek.
The in-form front-man, who bagged a quickfire international hat-trick in midweek, has not yet returned from Bulgaria and is a real doubt for Saturday.
Ferguson will now almost certainly call on Michael Owen in their absence, with the England hopeful desperate for playing time having been given scant opportunity to impress to date.
Fit again Edwin van der Sar will reclaim his place in United's goal at the expense of Ben Foster.
For the veteran Dutchman it is a welcome first appearance of the season after he broke two fingers during a friendly with Bayern Munich in July.
"Edwin plays tomorrow," said Ferguson.
"He had a reserve game 10 days ago and has come through that fine. He has been training for quite a spell now but with a hand injury you don't take any chances and that game has given him a good confidence boost."