Chelsea may benefit from its early elimination from Europe when Manchester United and Arsenal return to Premier League action hit by injuries sustained in the Champions League.
Defeat to Inter Milan two weeks ago means Chelsea's players were able to rest this week as they prepared for Saturday's trip to United, the only team ahead of the Blues in the standings.
But United will be continuing its attempt to win a record fourth-straight Premier League title without Wayne Rooney after the 34-goal striker damaged his ankle in Tuesday's defeat at Bayern Munich.
Third-place Arsenal's challenge may falter further if Wolverhampton Wanderers can exploit the absences of Cesc Fabregas, Andrey Arshavin and William Gallas after they got injured against Barcelona on Wednesday.
Chelsea lost 3-0 at Old Trafford last season but will be up against a team that has lost more than a third of its firepower with Rooney's absence.
"There is so much on the game on Saturday and the way we have played the last couple of games, we have to take that momentum and that same game plan into this match," Chelsea captain John Terry said. "We have to approach the game with no fear and we must go into it playing our own game.
"It is a tough place to go and the way we got beaten there and the way we played there last year was not good enough."
Rooney's absence could barely have come at a worse time for United, which leads Chelsea by just a point with six games remaining.
The Red Devils have to overturn a 2-1 deficit against Bayern next week and have tough matches against Manchester City and Tottenham looming in the second half of April. And Chelsea has scored 12 goals in its past two Premier League matches, including last week's 7-1 demolition of Aston Villa.
Teenage striker Frederico Macheda, who scored winning goals in two crucial matches at the end of last season, could have a role to play in place of Rooney.
"He's one of the most exceptional young strikers I've seen in my time at United," United manager Alex Ferguson said. "He has every chance of taking part in big matches."
Arsenal has the easier opponent but more wide-ranging injury problems before Wolves visit Emirates Stadium.
Arshavin said Thursday that he expected to be out of action for two or three weeks, which could also rule him out of the April 14 meeting with local rival Tottenham, while Gallas has a similar injury.
"I took a gamble that didn't pay off," Wenger said. "I can say 'yes, I regret that' now."
Wolves has won two away games in a four-match unbeaten run that has lifted it five points clear of the relegation zone.
Fourth-place Tottenham goes to Sunderland aiming for a sixth straight Premier League victory, while Manchester City plays at Burnley.
Also Saturday, Villa is at Bolton, Blackburn is at last-place Portsmouth and Hull is at Stoke.
Liverpool is at Birmingham on Sunday, when Everton hosts West Ham and Fulham hosts Wigan.
Newcastle could clinch promotion back from the second-tier League Championship with victory at Peterborough on Saturday and then over Sheffield United on Monday - if other results go its way.
Wins for Newcastle and defeats for third-place Nottingham Forest against Bristol City and Cardiff would end the Magpies' one-year absence from the Premier League.
