After Hendon Hooker left Thursday’s preseason opener against the Giants, Lions coach Dan Campbell confirmed he’s in concussion protocol. The former Tennessee star left after the third quarter and headed to the locker room after stopping at the injury tent. Hooker made a huge play when he trucked a defender to get a first down, but that was one of his final snaps of the night. Nate Sudfield returned as quarterback as the Lions fell to the Giants 14-3 in the first preseason game of the year. While it was unclear what the extent of Hooker’s injury was, the speculation was it was a concussion, Cam…