Manchester United are waiting to find out if Shinji Kagawa will be fit for Sunday's trip to Chelsea.
• Fergie flabbergasted by defence
• Jolly: Masters of the comeback
• Blog: The best and worst of United
Kagawa, 23 came off in Tuesday's Champions League win over Braga with a knee injury and could be missing as United approach a pivotal time in their season, with two trips to Chelsea - in the Premier League and the Capital One Cup - followed by Arsenal's visit to Old Trafford.
The Japan international, who has scored twice since his summer arrival from Borussia Dortmund, set up Javier Hernandez's first goal against Braga but was troubled before his half-time withdrawal.
United boss Sir Alex Ferguson said: "Kagawa twisted his knee. He struggled on for 20 minutes but we will assess in the morning because we don't know the extent of it at the moment."
Ferguson is definitely without goalkeeper Anders Lindegaard for a week after he suffered a thumb injury in training, which means 19-year-old Sam Johnstone will be on the bench at Stamford Bridge.