John Terry will have a scan on Monday to assess the extent of the knee injury he suffered on his return to domestic action after his four-match ban ended on Sunday.
The Chelsea captain was carried off on a stretcher after 39 minutes of the Premier League match against Liverpool at Stamford Bridge, 19 minutes after heading his side in front with his 50th goal for the club.
The game ended in a 1-1 draw.
Terry was in an accidental collision with Liverpool's Luis Suarez and his knee was injured as his leg buckled as he fell just outside his own penalty area.
Chelsea coach Roberto Di Matteo said it was too early to say how serious the injury was.
"He has a problem with the knee and he will have to have a scan in the morning," the Italian told Sky Sports.
"Hopefully it is not too serious, but at the moment we cannot say more."
Terry did not go to hospital and was seen to be bending the knee while being treated, but Di Matteo was not ruling out a cruciate ligament injury which could sideline him for the rest of the season.
He left the ground on crutches with his right knee in a brace.
"We will just have to wait for the scan. We don't exactly know the extent of the injury yet. It is a shame because he just got back from his ban as well."
Terry missed three Premier League matches and a League Cup tie against Manchester United after the FA found him guilty of racially abusing Queens Park Rangers defender Anton Ferdinand.
Suarez, who like Terry scored an unchallenged header from a corner to earn Liverpool a draw, was suspended last season for eight matches for racially insulting Patrice Evra of Manchester United.