Team officials said Kolb did not break any ribs or his sternum when two Bills defenders landed on top of him on a running play with 2 minutes remaining and his team trailing by a field goal. He was replaced by John Skelton who led the Cardinals to a score-tying 61-yard kick and back down the field again for what would have been a game-winning 38-yard field goal that kicker Jay Feeley shanked off the left upright.
Bills safety Jarius Byrd intercepted a Skelton pass deep in Arizona territory in overtime, leading to the Bills victory.
Cardinals Coach Ken Wisenhunt has not commented on Kolb's injury and the team hasn't disclosed details on the nature of it.
Skelton won the starting job out of training camp but went down with a sprained ankle in the team's season opener. Kolb took over and has had success, throwing for 1,169 yards and eight touchdowns with three interceptions. His offensive line hasn't done him any favors though, allowing a league-high 27 sacks.