Chelsea sweat on Terry injury
Terry, back for his first game after serving a four-match domestic ban, scored before being taken off in the 1-1 draw after an accidental collision with Luis Suarez.
The 31-year-old was in obvious distress when the injury occurred and Chelsea boss Roberto Di Matteo is hoping it is not as serious as it first looked.
"We'll know the extent after the scan," Di Matteo told the BBC.
"It was great to see him back and leading the team out and we just hope it is not a serious injury."
Terry's headed goal in the 20th minute sent the Stamford Bridge faithful into a frenzy but the mood in the stadium quickly turned to concerned silence as Terry collided with Suarez 19 minutes later.
He was seen leaving Stamford Bridge on crutches and his right knee in a brace.
"When a player like John reacts like that you know it is a painful one," said Di Matteo.
"When he started the game he scored the goal and showed the qualities he has. He showed his experience and influence. It was a real shame he had to come off."
Terry's injury could not have come at a worse time as the Blues face a tough away fixture against an in-form West Bromwich Albion next weekend followed by games against Juventus and defending Premier League champions Manchester City.
Di Matteo's men now sit third on the Premier League table, three points behind leaders Manchester United.