London - Wayne Rooney missed training for Manchester United on Monday raising doubts over his fitness for Tuesday's Champions League game against Benfica at Old Trafford.
The England striker played in the 1-0 Premier League win at Swansea on Saturday and there were no signs that he was injured, but he was not present when training got underway.
There was no immediate word from United about whether Rooney was injured, with Alex Ferguson likely to offer an update during this his pre-match press conference later on Monday.
Also absent was Northern Ireland defender Jonny Evans.
Defender Chris Smalling and striker Danny Welbeck, who both missed the weekend trip to south Wales because of injury, trained in a small group away from the main session, although previously Ferguson had indicated Smalling might be fit for Tuesday's game.