London:Liverpool needs to find a way to overcome the likely absence of Fernando Torres and Steven Gerrard or it could lose another must-win game against Birmingham on Monday.
Liverpool's reliance on the pair has been exposed by their continual injuries this season, leaving their team on verge of Champions League elimination and nine points off the top of the Premier League after just 11 games.
Monday's game at Anfield is the fifth in a row that fans and commentators have called crucial to the club's chances of mounting a challenge for a first title since 1990, but, worryingly for manager Rafa Benitez, his team has won just one of the previous four.
And Torres and Gerrard seem set to sit out the game, with both possibly needing surgery before they can resume the season.
Torres played in pain through 87 minutes of Wednesday's 1-1 Champions League draw at Lyon and visited a local hospital the following day for tests on his groin injury.
"He still had the same problems that have troubled him for a few weeks," Benitez said. "He wants to wait, rather than have an operation. He wants to work with the physios to try to solve his problems, but still he has pain.
"He told me he needed to keep stopping because of the pain. Whether there is the need for him or Steven Gerrard to have an operation is a decision we will not take straight away."
Surgery could rule either player out for weeks or even months, but both have the World Cup at the end of the season to think about as well as Liverpool's faltering form.
Although a 2-0 win over Manchester United alleviated some of the pressure on Benitez, a League Cup loss at Arsenal, a 3-1 Premier League defeat at Fulham and a last-minute equalizer by Lyon have heaped it back on.
If Chelsea beats United on Sunday, Liverpool could be 12 points behind the leaders by the time it plays.
Benitez may at least be able to bring back Martin Skrtel to shore up the defense, although Glen Johnson and Fabio Aurelio are out because of calf problems.
Chelsea hosts United boosted by the Court of Arbitration for Sport's decision to temporarily lift FIFA's ban on it signing new players, while the defending champions are struggling with injuries and a porous defense.
England international Rio Ferdinand will miss the match because of what may be a lower back problem, while Wes Brown and Jonny Evans looked shaky as United let in three goals in a Champions League draw against CSKA Moscow this week.
Midfielder Park Ji-sung is again missing with a knee problem and Gary Neville is suspended, but Nemanja Vidic and Dimitar Berbatov are fit.
"Vidic has trained for the last three days and should be OK," Ferguson said. "Berbatov got a knock and we'll see what he's like in training today, but he should be fine."
And United should soon be able to call upon Owen Hargreaves, with the England midfielder set to return to training in about 10 days - 14 months after his last appearance.
"He's been doing some good football work with our physios," Ferguson said. "We're not going to force it, but he is very happy within himself."
Any slip-up by United could let Arsenal through into second place, with the Gunners at lowly Wolverhampton Wanderers in one of Saturday's five matches.
The Gunners are seeking to stretch a two-month unbeaten streak in which it has outscored its league opponents 19-5.
Arsenal is just three points behind United, which, with Chelsea, has occupied the top two spots since Sept. 13.
Also Saturday, fourth-place Manchester City hosts Burnley, Tottenham hosts Sunderland, Aston Villa hosts Bolton and bottom club Portsmouth is at Blackburn.
West Ham hosts Everton on Sunday, when Fulham is at Wigan and Stoke is at Hull.
Newcastle seeks to stay top of the second-tier League Championship when it plays Peterborough on Saturday, with second-place West Bromwich Albion at fourth-place Leicester.