Newly reinstated John Terry scored Chelsea's only goal in the 20th minute, then went down with an apparent knee injury 18 minutes later in the Blues' 1-1 Premier League draw with Liverpool on Sunday.
The 31-year-old defender was stretchered off looking in discomfort after accidentally colliding with Liverpool striker Luis Suarez and having his knee buckle. There was no immediate word on the severity of the injury.
"He has just got into the team after the ban ... we just hope it isn't a serious injury and he is back soon," Chelsea manager Roberto di Matteo said, adding that the injury will be assessed in the hospital on Monday.
Terry could be facing a long spell on on the sidelines if the injury to the knee he had surgery on in February turns out to be serious. He was was consoled by di Matteo before disappearing down the tunnel.
"I was concerned about his well-being," the Italian said. "We just got him back into the team after the ban. It was great seeing him out there."
Chelsea's defense had been bolstered by the return of its veteran captain, who took the field Sunday after serving a four-game domestic ban for racial abuse.
Terry headed in his 50th Chelsea goal from Juan Mata's corner in the 20th minute after missing the last four domestic matches for racially abusing an opponent.
Liverpool had barely troubled Chelsea but Suarez was given the space to head in an equalizer in the 73rd minute.
The draw leaves Chelsea in third, three points behind leader Manchester United, while Liverpool is languishing in 13th place.
Information from Press Association and The Associated Press was used in this report.