Chelsea will have to wait for further tests to learn the extent of N'Golo Kante's injury after he limped off their 3-0 win over Watford on Saturday night.
The midfielder went down on 78th minute clutching what seemed like his hamstring, with Chelsea leading 2-0, and was replaced by youngster Billy Gilmour.
Speaking after the match, coach Frank Lampard said he could not tell the extent of the injury and that the Frenchman will have further scans to determine how bad it was.
"Kante has got a small hamstring issue," revealed the manager.
"He'll have a scan tomorrow so we'll have to see how bad it is but I'm guessing it will be a problem for Crystal Palace on Tuesday,"
The midfielder, who has started all Chelsea's matches since the restart, is now a doubt for their match away to Crystal Palace on Tuesday.
Even though Chelsea have plenty of options in the middle of the pack, his absence might be a worry for Frank Lampard as his side embarks on an eight-day busy Premier League schedule.
After their trip to Selhurst Park on Tuesday, the Blues will be in action on Saturday away to Sheffield United, before a home tie against Norwich on Tuesday.
The win against Watford on Saturday was however a welcome relief, after their shocking 3-2 loss away to London rivals West Ham in mid-week.