Warren, who missed all of last season with a dislocated ankle, was an exclusive rights free agent, meaning the Buccaneers were the only team that could re-sign Warren before free agency began on Feb. 29.
Warren was on his way to a roster spot before injuring his ankle in the final preseason game on Aug. 30 against Houston. The injury, some believed, threatened Warren's career. But during the Bucs' final locker room availability in January he said the injury was fully healed and that he would be ready for offseason workouts.
Some, including Bucs GM Bruce Allen, have credited Warren's injury with galvanizing the team early in the season.
Warren automatically becomes a player in a murky wide receiver battle where veterans Joey Galloway and Ike Hilliard are the only sure things. Michael Clayton is under contract but remains an enigma, while Maurice Stovall is rehabbing an elbow injury suffered against San Francisco on Dec. 23.
The Bucs have not announced the signing.