Chelsea’s towering defender Robert Huth will be out for six to eight weeks with knee ligament damage, the London club have confirmed.
The German international had only just returned to action after an ankle injury and scored in the 2-0 win over Birmingham City on Sunday.
“He was really unlucky because someone fell on him,” Chelsea physio Mike Banks told the club website.
“At least he won’t need surgery.”
Chelsea face Blackburn on Wednesday looking to stretch their lead at the top to 11 points after Manchester United beat Arsenal 4-2 on Tuesday.
Assistant manager Steve Clarke expects the squad to be fresh after rotating players for the Birmingham tie.
“We made eight changes at the weekend from the Manchester United game a week ago,” Clarke said.
“Those who played against Manchester United but not Birmingham had a couple of days off, and then a couple of days just ticking over, and they’ve only just stepped up training for the last two days.”