Pittsburgh Steelers quarterback Ben Roethlisberger has sustained a knee injury in his side's clash against the St Louis Rams.
The incident occurred in the third quarter of the match at Edward Jones Dome when he was sacked by Mark Barron.
Roethlisberger fell to the ground and was seen clutching his knee, which resulted in him being carted off the field, ruling him out for the rest of the match.
The Steelers confirmed that the 33-year-old suffered an injury to his left knee, but did not reveal the severity of the problem.
Roethlisberger last missed time in the 2012 season.
