Manchester United are hopeful that Wayne Rooney and Nemanja Vidic will be fit for the Champions League semi-final second leg against Barcelona.
Neither player trained on Monday morning after sustaining injuries in the 2-1 defeat at Chelsea on Saturday.
Striker Rooney limped off with a hip problem after scoring, while defender Vidic was cut badly after being hit in the face by Didier Drogba's knee.
United are seeking a spot in the Moscow final after a 0-0 draw at the Nou Camp.
Both Rooney and Vidic are key figures for United, and manager Sir Alex Ferguson will give them as much time as possible to prove their fitness for Tuesday's match.
"It's a difficult one. We think both could make it but I can't be certain about that," said Ferguson.
Following the Premier League defeat at Stamford Bridge, Ferguson said England international Rooney was suffering with the same "very painful" hip knock which he suffered a week earlier at Blackburn.
He also confirmed that Serbian centre-back Vidic, who missed the semi-final first leg in Barcelona with a stomach bug, had to have stitches under his lip after losing a tooth in the accidental clash.
Barcelona, meanwhile, will welcome back skipper Carles Puyol who will replace the suspended Rafael Marquez in defence.
Midfielder Yaya Toure (ankle) is a doubt and Edmilson could replace him.