CINCINNATI -- Cincinnati Bengals offensive lineman Andrew Whitworth missed Thursday's practice after suffering a concussion in Wednesday's workout, according to Bengals officials.

The Pro Bowl lineman, who was moved from the outside of the offensive line to the inside three weeks ago, made it on the injury report released after Thursday's walkthrough, joining two other Bengals starters on the team's concussion protocol.

Defensive end Carlos Dunlap and linebacker James Harrison haven't practiced this week after sustaining concussions in last Sunday's game at Pittsburgh. Dunlap, whose concussion is believed to have come on the last play of the game, ran through conditioning drills off to the side during the portion of Thursday's session that was open to media.

Whitworth, like Harrison, didn't participate in the practice in any capacity. The lineman spent much of the practice wearing a hooded sweatshirt and standing off to the side.

If the Bengals were to be without Whitworth on Sunday when they host the Minnesota Vikings in a game that bears playoff and division-title implications, it would be the third time the eight-year veteran missed a game this season.

Whitworth didn't play in the opener against Chicago and was unable to go on Halloween when the Bengals visited Miami. Backup Anthony Collins, who has moved into the starting rotation at left tackle since Whitworth was moved from tackle to left guard during the Dec. 1 win at San Diego, filled in for Whitworth in those two games. He likely would stay at tackle, and right guard Kevin Zeitler likely would be forced back into the starting rotation.

Zeitler has been out the past month nursing a foot injury. He's been active the last two games but hasn't played. His backup, Mike Pollak, has handled all the right guard duties.

With Whitworth at left guard, the Bengals have had some of their best offensive performances of the second half of the season. Not only have they rushed for more than 150 yards as a team in two of the last three games, but quarterback Andy Dalton has been sacked only once in the last four games.

Cornerback Terence Newman, who still is battling through a knee injury, also didn't practice Thursday. Neither did defensive tackle Devon Still, who has a back injury that popped up Wednesday.