Injuries and international commitments means head coach John Mousinho will be forced to reshuffle his pack for the game against the League Two side.
However, he’ll be confident that the ‘strong’ side he puts out will be a match for the Priestfield outfit.
Here’s how we think the Blues will line up for their second game in this season’s competition.
9. Right wing 1: Gavin Whyte
The Northern Ireland international is available after being left out of Michael O'Neill's latest get-together. Pompey fans will understand that decision, with the former Cardiff and Oxford man yet to ignite the Fratton faithful following his summer arrival. Tonight's game could be the perfect opportunity for Whyte to do that and kick-start his Pompey career. Photo: Jason Brown
10. No10: Tino Anjorin
The on-loan Chelsea midfielder was handed his first league start against Wycombe last Tuesday night but found himself back on the bench against Port Vale on Saturday. Will no doubt be given the chance to build his fitness and show the Fratton faithful what he's made off against the Gills tonight. Photo: Jason Brown
11. Left wing: Abu Kamara
With Kusini Yengi pushing to get back into the side, John Mousinho might be tempted to rest Kamara, who has featured in every Pompey game this season. Yet tonight would be another opportunity for the on-loan Norwich midfielder to boost his ever-growing confidence. Plus, Yengi is unlikely to be 100-per-cent fit. Photo: Jason Brown
12. Centre-forward: Christian Saydee
There's no point in risking Colby Bishop tonight - and with Christian Saydee back fully fit, there's a fan favourite ready to step in and fill those boots. Photo: Jason Brown