Chelsea striker Diego Costa will play against Manchester United, providing he trains in full on Saturday.
The Spain international, 26, spent a night in hospital earlier this week with a viral infection.
He has been recovering at home but ahead of Sunday's game at Old Trafford, Blues boss Jose Mourinho said: "I want to play Diego if he is ready.
"He has to show on Saturday in training that he's capable of playing. If he's ready to play, he plays."
With Loic Remy definitely out of the United game because of a groin injury sustained in Chelsea's Champions League win over Maribor,the Blues could do with £32m Costa being fit and available.

Costa's Chelsea campaign
Burnley 1-3 Chelsea - scored, booked
Chelsea 2-0 Leicester - scored
Everton 3-6 Chelsea - scored two, booked
Chelsea 4-2 Swansea - scored hat-trick
Chelsea 1-1 Schalke - failed to score
Man City 1-1 Chelsea - booked
Chelsea 2-1 Bolton - failed to score
Chelsea 3-0 Aston Villa - scored
Sporting Lisbon 0-1 Chelsea - failed to score
Chelsea 2-0 Arsenal - scored
The frontman has scored nine goals in seven Premier League games despite a persistent hamstring problem, but has missed the last two matches.
He was then laid low by a virus and barred from attending the club's training ground in Surrey.
"Everything has happened to him and being ill obviously didn't help his recovery process because we didn't want him at Cobham," said Mourinho. "The medical staff were going to meet him at his house."
Asked what Costa needed to do to be involved against United, Mourinho added: "He has to train without any limitations, to make a complete training session with the other guys, without any kind of protection."
John Mikel Obi, Ramires and Andre Schurrle could all return after injury and illness, but Cesar Azpilicueta begins a three-match suspension after being sent-off at Crystal Palace.