Lions quarterback Jon Kitna felt a twinge in his back while warming up and decided not to play in Saturday night's exhibition game against the Colts. Kitna missed two days of practice during the week because of back spasms. Coach Rod Marinelli left the decision up to Kitna on whether to play against the Colts. Kitna said he felt the twinge when he threw a fade pattern. Backup J.T. O'Sullivan started and played the entire game, a 37-10 loss to the Colts. "They left it up to me," Kitna said. "It was totally my call. Then I got a little twinge. There was no reason to push it."