Manchester United could be without both Marouane Fellaini and Rafael for their Champions League showdown against Bayern Munich tomorrow after the pair missed training today.
There was some better news elsewhere on the injury front however - Wayne Rooney, Rio Ferdinand, Jonny Evans, Ryan Giggs and Patrice Evra all took part in the session, although Robin van Persie is still out of action.
Fellaini featured for Manchester United in their 4-0 win over Newcastle, while Rafael missed that game and the first leg against Bayern, with Antonio Valencia providing cover in his absence.
Rooney missed the game at St. James' Park with a toe issue that manager David Moyes said was causing him serious discomfort, however having taken part in training this morning is likely to start at the Allianz Arena.
Manchester United go into the game against the German champions on the back of some encouraging results after a disappointing season.
Moyes' men were huge underdogs going into their quarter-final against Munich but earned a creditable draw in the first leg at Old Trafford, which they followed up with the comfortable win against Newcastle.
While Pep Guardiola's side are heavy favourites to progress to the last four, Moyes says his team are ready to spring a surprise.
We'll go toe-to-toe with them," the Scot said after the first leg.
"Our best football has been in this competition, and we will need to show our best football when we go to Bayern next week."