The on-loan Swindon forward was stretchered off midway through the first half of Saturday's defeat at Plymouth having suffered an ankle injury, but scans have confirmed a ligament sprain.
Benson will definitely miss the upcoming fixtures against Gillingham and Exeter, but is being pencilled in for a possible return for the final-day home clash against Bradford and any potential play-off involvement.
Cheltenham's senior sports therapist Ian Weston told the club's official website: "He has an outside chance for Bradford.
"It was as we expected. Paul has a grade one sprain of the deltoid ligament and one of the tendons round the back of the ankle bone.
"The indications are that he will be out for the next two games, but could make the Bradford game if all goes to plan and it settles down well."