Manchester United captain Roy Keane is set to miss the Premier League leaders' game against Everton at Old Trafford on Friday, manager Alex Ferguson said on Wednesday.
"We have only one doubt and that's Roy Keane with a hamstring injury," Ferguson told a news conference.
"It was tight. It wasn't a pull or anything but nonetheless we'll assess it on Boxing Day.
"I may not have played him anyway but we will have to make sure he's fit for the Sunday game.
"There's a possibility of two or three changes but no more than that."
Keane came off near the end of United's win over Tottenham last Sunday which took Ferguson's side to the top of the table, and will now be held back for Sunday's trip to Middlesbrough.
United lost at Middlesbrough last Christmas before going on an 18-match unbeaten run, including 15 wins, to lift the title.
FEW MISTAKES
Ferguson is keen to avoid any major slip-ups over the holiday period with Arsenal and Chelsea just a point behind the leaders.
"The way the top three are there are very few mistakes made, so it's important not to make any," Ferguson added.
The United manager confirmed that England international defender Wes Brown is almost ready for a first-team return and his comeback from a knee injury will add to Ferguson's central defensive options.
Rio Ferdinand is still available pending a possible appeal against his eight-month ban imposed last week by the FA for failing or refusing to take a drugs test.
United have asked the FA for a written explanation of the reasons behind the verdict and punishment before deciding whether to lodge an appeal.
Earlier, Ferguson again defended Ferdinand, telling MUTV: "I keep examining the whole procedure at United and wondering if we're right or wrong.
"I look at Rio and conclude that we have to support him because there's absolutely no evidence at all here.
"This is why we're supporting him. He's our player. We're going to get a lot of criticism because of it but we're entitled to support somebody we feel is innocent.
"He knows he's innocent. He was wrong not to go there (to the test). We know that. But we'll just have to keep supporting him."
Meanwhile, Ferguson is also hoping to welcome back striker Ole Gunnar Solskjaer in January following knee surgery.
Ferguson told a news conference: "We have got him pencilled in for January 15 for a reserve game against Birmingham. He's training very well and coming along nicely."
