TAMPA — The Bucs could be without Ali Marpet for the third straight game. The starting left guard, who hasn’t played since Nov. 2 against the Giants, did not practice Friday and his status doesn’t look promising for Monday night’s game against the Los Angeles Rams.Marpet remains in concussion protocol. He practiced Thursday and was expected to be re-evaluated Saturday. Marpet has had lingering, mild symptoms. The Bucs held a night workout at Raymond James Stadium on Friday.If Marpet is unable to play, the Bucs likely would use veteran A.Q. Shipley at center and move Ryan Jensen to left guard. That combination was effective in the Bucs’ 46-23 win over Carolina, in which running back Ronald Jones rushed for a career-high 192 yards, including a 98-yard touchdown run.