Manchester United manager Alex Ferguson backed captain Roy Keane's decision to consider playing on past his planned retirement date.

Keane, 33, had intended to end his playing career when his current contract at Old Trafford expires in June, 2006.

But Keane has now said he is tempted to play beyond that date if he is still fully fit and still required by the club he joined from Nottingham Forest in 1993.

"I'm not surprised the way he's playing. He's in fantastic form," said Ferguson at a news conference on Thursday.

"It's his best (form) of the season. He's really come to the forefront of his game.

"And in that form, if I was him, I would want to stay on playing too."

Keane has helped United win five of their last six games to get within nine points of English Premier League leaders Chelsea going into the important Christmas period.

United play Bolton, Aston Villa, Middlesbrough and Tottenham and Ferguson expects his side to come out the other side well placed in the title race.

"It's the start of the run-in. When you're through December there are sometimes casualties in terms of teams dropping points you don't expect," he said.

"What pleases me is that our form has hit at the right time. When we get through this period to January 4 after the Tottenham game, there is the FA Cup to follow and we can assess where we are and where the whole league is and hopefully we're right on the tails of the leaders.

"There is a great consistency in our performance. What we want now is consistency of results. In the run-in, as is proven over the years, we make less mistakes after New Year than we do before it."

Gabriel Heinze and Cristiano Ronaldo return to United's squad for the Boxing Day visit from Bolton after being given a rest by Ferguson.

However, strikers Ruud Van Nistelrooy (Achilles tendon) and Louis Saha (knee) remain sidelined and will miss the holiday programme.