Manchester United striker Dimitar Berbatov will return to the squad for Sunday's trip to Arsenal after the Premier League's top scorer missed three games through injury.
"He had a slight groin strain but he has trained all week," manager Sir Alex Ferguson told a news conference.
Ferguson has been amazed at how Arsenal's title challenge has fallen away after the London side were last month just three points behind with a game in hand.
"I have been a bit surprised (by Arsenal)," Ferguson said. "But Chelsea were the dark horses in the sense that people seemed to think they were out of it. I looked at their programme and thought they had an easier run-in and they are now on our coat tails."
Arsenal manager Arsene Wenger believes the turning point in his team's season was February's League Cup Final defeat by Birmingham City as, since then, they have seen their challenge for four trophies evaporate.
"I feel that the team gave a lot in the last two months but since we lost in the Carling Cup everything turned a little bit against us," he said on the club's website.
Tottenham Hotspur midfielder Tom Huddlestone is a major doubt for Saturday's trip to Chelsea with an ankle injury, the club said on its website.
Spurs added that he was joined on the sidelines by left back Benoit Assou-Ekotto, who injured his hamstring during last week's draw with West Bromwich Albion.
Chelsea manager Carlo Ancelotti has a full squad to choose from as his side seek to close the gap on leaders Manchester United to three points before their title rivals play on Sunday.
"Ramires and Essien had problems at the start of the week, now they are ready and fit," Ancelotti said on the club's website.
Liverpool striker Andy Carroll comes up against his former club Newcastle United on Sunday for the first time since his move in January and his manager Kenny Dalglish is confident the 22-year-old will be able to handle the reception from fans.
"I don't know what they will do on Sunday but if, as a player, you don't get abuse off your old supporters then they can't have been too disappointed that you left," Dalglish said on the club's website.
Aston Villa travel to West Bromwich Albion on Saturday still without manager Gerard Houllier but happy that he left hospital on Thursday evening after being admitted with chest pains last week.
"Gerard Houllier was discharged from the coronary care unit at the Queen Elizabeth Hospital," the club said on its website.
Birmingham City striker Obafemi Martins has been ruled out for the rest of the season after having an operation to repair a stress fracture in his leg, the club said.
The Nigerian, on loan from Russian side Rubin Kazan, scored City's winner against Arsenal in the League Cup Final in February, last featured as a second-half substitute against Wigan Athletic in mid-March.
