The Detroit Lions have more injury issues on the offensive line. Guard T.J. Lang is in concussion protocol, coach Jim Caldwell told reporters on Thursday. Lang's concussion symptoms developed during Wednesday's practice stemming from Monday's victory in Green Bay. The concussion didn't happen during practice, per Caldwell. The concussion puts Lang's availability for Sunday's matchup against the Cleveland Browns in doubt. The veteran guard will need to pass through protocol. Lang's injury is the latest for a struggling Lions offensive line that is hoping to get starting left tackle Taylor Decker back soon after offseason shoulder surgery.