Manchester United could be facing a personnel problem for their final Champions League group match against Shakhtar Donetsk at Old Trafford on Tuesday night.
David Moyes' side have already booked their place in the last 16 but require a point against the Ukrainian title winners to seal top spot in Group A and avoid most of Europe's heavyweights in next week's knock-out round draw.
However, Nemanja Vidic, Patrice Evra, Chris Smalling and Marouane Fellaini were all missing from the open section of Monday morning's session at the Aon training complex.
With Michael Carrick also ruled out by an Achilles injury and Darren Fletcher not registered for European competition, Moyes may not have the resources available that he would like.
After back-to-back home Premier League defeats, victory is important for United as they look to boost their flagging morale.
Former Everton boss Moyes is now trying to get as much as possible from his squad after they dropped to ninth in the top flight with the departure of Sir Alex Ferguson clearly having had a seismic effect.
"We've got roughly the same squad that was champions last year," Moyes said.
"We've not changed an awful lot in that period.
"I need to make sure I'm getting the best out of the players and we are performing as well as we possibly can.
"I do think we can play better but there were a lot of games last year where Manchester United didn't play particularly well and maybe, in a game like that, sneaked it with a goal."