United have been given a huge boost ahead of this weekend's clash with Chelsea, following the return from injury of influential defender Rio Ferdinand.

The England international has missed the Reds' last four matches after suffering a recurrence of a back injury, but SIr Alex Ferguson has confirmed that he will return on Sunday.

"Rio's fit to play," the manager told his pre-match press conference. "He's missed the last few games, and that's given us time to get things settled down. He's very good, he's trained for the last few days and he's feeling much better.

"He's one of the best centre-backs in the world, and he does make a difference because he's got the stature and presence to play in these big games."

Ferdinand is part of an almost fully fit United squad for this weekend's match, with only long-term injury victims Wes Brown and Owen Hargreaves ruled out, and Patrice Evra back from suspension.

"We had 24 players training this morning," said Sir Alex. "Patrice will be the freshest man on the pitch on Sunday. He’s had a nice break, but he’s training well, he’s looking forward to it and it’s a great boost because he’s been fantastic this season. So we've everyone fit for Sunday except Wes and Owen, which is a really good position to be in."