Pompey are waiting to learn the extent of Ryan Tunnicliffe’s hamstring injury.
The midfielder limped off the pitch late in the first half of Saturday’s League One win over Bolton at Fratton Park.
It means he is unlikely to feature when Cheltenham visit the south coast for another home contest on Tuesday night.
But Joe Morrell could make a return to the starting line-up after Danny Cowley revealed he was only fit enough for a place on the bench against Wanderers.
The Blues boss said: “Ryan is having a scan later today, so we’ll know more about that when we get the results back.
"Joe had a niggling groin problem and we’ve got a busy run of games at the moment, but he should hopefully be available from the start."
“The early signs and his symptoms suggested it was more of a neural issue than a muscular one, so we hope that’s the case.
“Joe had a niggling groin problem and we’ve got a busy run of games at the moment, but he should hopefully be available from the start.
“We’ve already got some key injuries in defensive areas and only have 18 senior players available at the moment.
“That will give Gassan Ahadme a chance to come back into the matchday squad, though, and he’s been training well.
“We’ve also had Harry Jewitt-White, Harvey Hughes and Izzy Kaba around the first team squad in training, so it could open up an opportunity for them.”