Manchester United are waiting to discover the extent of knee injuries suffered by Nemanja Vidic and Ashley Young, who were both forced off during Sunday's victory over Liverpool.
The 2-1 win at Old Trafford maintained United's seven-point lead at the top of the Premier League but it may have a come at a price, with Young being replaced by Antonio Valencia at half-time and Vidic making way for Chris Smalling during the second half.
The injured pair are set to be assessed on Monday and with United in action on Wednesday against West Ham in their FA Cup third round replay, boss Sir Alex Ferguson will be hoping for a positive prognosis.
Defender Jonny Evans is expected to miss that game, with Ferguson revealing on Sunday that the centre-back was absent against Liverpool because of a hamstring complaint.
"Jonny Evans felt his hamstring yesterday afternoon," Ferguson told MUTV. "I was at Nottingham [watching Forest v Peterborough] and got a message at half-time.
"He trained in the morning so it was strange. But Vidic and Ferdinand are experienced and you can't say any more than that. They were brilliant."
United face a tricky Premier League trip to Tottenham this Sunday.