Manchester United boss Sir Alex Ferguson has admitted Wayne Rooney and Patrice Evra were left out of the squad to play West Ham United as they have suffered setbacks in their recovery from injury.
Both the England striker and France full-back were expected to be on the bench for Sunday's 1-0 win at Upton Park after returning to training last week.
But Ferguson has revealed Rooney's hamstring problem and Evra's foot niggle have yet to fully clear up.
"They had little setbacks in training," he told MUTV. "They didn't do a lot last week, which was partly to do with the weather.
"They needed another three or four days' training before we could start considering them.
"I think the important thing about having injuries with the squad we've got, you don't take chances. It proves fatal. We weren't prepared to take a chance with them."
The pair have been pencilled in for comebacks in next weekend's FA Cup fifth round meeting with Derby County.