Chicago Bears quarterback Jimmy Clausen, who made his first start in four years, was diagnosed with a concussion Sunday evening after experiencing delayed symptoms and will not play this week.

Coach Marc Trestman started Clausen and benched Jay Cutler for Sunday’s game against the Detroit Lions, who won 20-14.

Clausen is being evaluated based on the NFL’s concussion protocol.

Clausen was hit on a play which drew an unnecessary roughness penalty in the final offensive drive of the game. He was monitored by the team’s medical staff.

Clausen exhibited no signs of concussion immediately after the hit or during the final four plays of the drive. At the conclusion of the series, he was further checked on the sideline and again exhibited no signs or symptoms. After the game he passed all testing by team physicians and reported no concussion symptoms.

The Bears told Clausen before he left the stadium to contact team athletic trainers if he had any problems later in the day. Clausen experienced delayed symptoms Sunday evening and contacted trainers. He was taken to a hospital where he was further examined by a team physician and diagnosed with a concussion.

Clausen completed 23 of 39 passes for 181 yards with two touchdowns, one interception and a 77.0 passer rating.