Pittsburgh Steelers head coach Mike Tomlin has confirmed that quarterback Ben Roethlisberger sustained an MCL injury in his side's win over the St Louis Rams.
The incident occurred in the third quarter of the match at Edward Jones Dome when the 33-year-old was sacked by Mark Barron, which resulted in him being carted off the field and unable to return to the game.
Roethlisberger underwent an MRI scan on Monday, which revealed that he had sustained an MCL injury, ruling him out of action for the near future.
Reports suggested that the quarterback will face up to six weeks out, but Tomlin refused to confirm the duration of Roethlisberger's absence.
He told reporters: "The MRI on Sunday night revealed Ben Roethlisberger had an MCL injury to his left knee.
"There is no timetable for his return, but Ben is a competitor and we are confident he will do everything in his power to return at the appropriate time."
Roethlisberger will be replaced by Michael Vick as the club's starter in his absence.
