Dawkins missed last weekend's game against New England with the same injury, and he aggravated it during the first quarter against the Bills.
Urbik walked off the field early in the second quarter after getting hurt during Buffalo's final possession of the first quarter. He was replaced by Colin Brown.
Brown became the fourth center that Buffalo has used this season after starter Eric Wood sustained a season-ending knee injury in a 44-7 loss at Dallas on November 13.
Copyright 2011 by The Associated Press