Chelsea centre-back Thiago Silva has damaged the ligaments in his knee and will undergo rehabilitation, the Premier League club said on Tuesday.
The Brazil international picked up the injury in the first half of their 2-0 defeat at London rivals Tottenham Hotspur in the league on Sunday.
The 38-year-old underwent further assessment and a scan on his return to the training centre on Monday, the club said.
"Scan results from those assessments have confirmed damage to Thiago's knee ligaments and he will now work closely with the club's medical department during his rehabilitation to return to action as soon as possible," Chelsea said in a statement.
The defeat at Spurs extended Chelsea's miserable run under manager Graham Potter, with the team having won only two of their last 15 games in all competitions.
Chelsea are 10th in the league with 31 points after 24 games, 14 points outside of the top four. They host Leeds United on Saturday.
