Kolb was tackled hard by Sedrick Ellis as he let go of a pass for his only completion in three series on Sunday night. Kolb landed hard on his right side, got to his knees and put his helmet on the ground, staying down while trainers talked to him. He walked off the field without assistance after a couple of minutes.
Kolb and John Skelton are competing for the starting job. Kolb had a rough night -- his first pass was intercepted. Kolb finished 1 of 4 for 4 yards.
"He has a bruise in his chest and that makes it kind of tough to rotate, move," coach Ken Whisenhunt said after the team's 17-10 loss. "I think he'll probably be practicing sometime this week."
Skelton took over and went 4 of 6 for 32 yards.
"You never want to have an injury in the preseason, especially an early game like this, having to play that fifth preseason game," Skelton said. "But he will be OK."
In his first year with the Cardinals, Kolb started nine games and threw for nine touchdowns with eight interceptions as Arizona went 8-8. After coming over from the Philadelphia Eagles, Kolb had to learn a new offense on the fly because of the lockout.
Skelton got the starting nod while Kolb was out last season and and went 5-2 as a starter.
Information from The Associated Press was used in this report.