Baltimore's top cornerback,
Webb was covering Dallas Cowboys wide receiver Dez Bryant in the first quarter when the two made contact and Webb crumbled to the turf clutching his knee.
Webb was helped off the field by trainers, barely putting any weight on his left knee. He is quetionable to return.
It's the opposite knee to the one Webb had surgically repaired after an ACL tear in his rookie season.
Webb, who the Ravens signed to a six-year deal this offseason, entered the game with 25 tackles, six pass deflections and one interception.
Pro Bowl defensive tackle
Ngata returned to the field late in the second quarter.