Defender prepares for Fratton Park return.
The match will see him return to the club with whom he started the season, along with winger Jack Compton who also signed for the U's from Pompey during the January transfer window.
Josh was substituted at half time in the 2-0 win against Walsall last week, but returned to training in the back half of this week to make himself available for the match at Fratton Park.
U's defender Josh Thompson is set to be fit and ready for the match against his former club Portsmouth this weekend.
Jack got another ninety minutes under his belt in the U's U21s match against Charlton in midweek, but the match comes too soon for midfielder Kem Izzet, who saw a specialist earlier this week about his ankle injury.