Kitson sat out Pompey's 0-0 draw with Charleston Battery at their training camp in South Carolina with a thigh injury.
It meant boss Steve Cotterill could only use five substitutes, once again highlighting how thin the Fratton Park squad is.
"Kits has got a thigh injury," said Cotterill. "We just need to see how that one is leading up to the weekend.
"We're still trying to get players in but it's easier said than done to get good players into your squad. It's something we'll continue to work at.
"The owners have been very good since they've come in and backed me very well. They know the squad is light and are trying to address that."