New signing Loic Remy has picked up what appears to be a groin injury.
The Frenchman injured himself as he put the Blues 1-0 up in their Champions League clash against Maribor earlier this evening.
Blues boss Jose Mourinho immediately substituted the 28-year-old as soon as it became apparent the former QPR man wouldn't be able to continue.
Remy's injury gives the Special One a massive headache ahead of Sunday's trip to Old Trafford.
The Special One is already without the services of top goal-scorer Diego Costa, and the injury to Remy couldn't have come at a worse time for former Real boss.
The Chelsea chief will now have to start veteran striker Didier Drobga for their crunch match against Louis van Gaal's side.
But starting Drogba could be a major risk, as the 36-year-old has only just recovered from an ankle injury.
