CINCINNATI -- One day after giving their players a day off, the Cincinnati Bengals placed four under the concussion protocol Wednesday.
At least one of the injuries dates back to Sunday afternoon's practice.
Linebackers J.K. Schaffer and Jayson DiManche joined tight end Kevin Brock and offensive tackle Andre Smith on the protocol list. Schaffer's injury occurred Sunday, the last day he practiced. Smith's injury goes back to Monday when he was helped off the field during the second straight fully padded day the Bengals had this training camp. DiManche's apparently occurred that day, too.
Brock, who practiced early Wednesday, was added to the protocol following the workout.
Of the players on that list, Smith's name is the biggest. The sixth-year veteran is the team's starting right tackle. With starting left tackle Andrew Whitworth nursing a calf injury since before camp began, the Bengals are now thin along the edges of their offensive front. Veteran free-agency addition Will Svitek has seen action in his place.
Schaffer and DiManche are in a battle for linebacker spots, while Brock would be the team's fourth tight end if the position group was at full health. Jermaine Gresham still is out with a back injury suffered this offseason. He, Whitworth, receiver Marvin Jones, quarterback AJ McCarron and receiver Ryan Whalen remain on the team's active injury lists.