The striker missed last Saturday's goalless draw against Preston with a virus but has returned to training this week.
Jake Jervis took Benson's place in the starting line-up at the weekend so he could be the man to make way if the former Dagenham frontman earns an immediate recall.
Benson's return means caretaker boss Guy Whittingham has a fully-fit squad to choose from.
Nathaniel Mendez-Laing and Lee Williamson came off the bench against Preston and will be pushing for places in the starting line-up should Whittingham change things around with Pompey winless in 10 matches.
They are back in the relegation zone and still have the possibility of a 10-point penalty hanging over them.