Updated Nov. 11, 2012 at 11:37 p.m. CT

By Adam Hoge-

SOLDIER FIELD (CBS) Bears quarterback Jay Cutler suffered a concussion in the first half of Sunday night’s game against the Houston Texans and did not return.

Cutler took a number of shots in the first half, but did not miss a play. After halftime, he did not return and backup quarterback Jason Campbell took the field with the offense.

Bears head coach Lovie Smith said he didn’t know what play caused the concussion and added that Cutler did not show any concussion symptoms until halftime.

“He didn’t have any symptoms (before halftime),” Smith said. “There were a lot of hard hits out there today. You can’t start taking guys out for that. When they’re injured, then we take them out. But before that? No.”

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Still, it appeared the concussion occurred with 2:56 left in the second quarter when Cutler was hit illegally by Texans linebacker Tim Dobbins and stayed on the ground for a few moments before getting up. Cutler completed the pass to Devin Hester for a 42-yard gain on the play, but it was called back because Cutler was ruled to have crossed the line of scrimmage before throwing the ball. Dobbins was called for unnecessary roughness and the penalties offset. Three plays later, Cutler was intercepted for the second time in the game.

NFL rules require players showing signs of a concussion to leave the game, but Brandon Marshall added that everything “seemed normal” in the huddle late in the second quarter. Cutler finished the game 7-of-14 for just 40 yards and two interceptions.

Smith said Cutler’s concussion symptoms started to clear up during the second half and added “we’re hopeful” when asked about Cutler playing next Monday against the 49ers.

Bears rookie defensive end Shea McClellin also left the game with a concussion and did not return. He suffered the injury on the Texans’ first offensive possession.

There were reports before last April’s NFL Draft that McClellin suffered three concussions in college at Boise State, but he refuted those reports, saying he only suffered one.

Cutler suffered a concussion in 2010 and missed a game. He also reportedly suffered one earlier in his career in Denver and another in college at Vanderbilt.

For more Bears coverage throughout the season, follow Adam on Twitter at @AdamHogeCBS.

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