Paul Cook revealed he has ‘one or two’ injury doubts heading into tomorrow night’s game.
That scenario is set to spark enforced changes to the side so impressive in victory at Colchester.
Pompey’s boss, however, is tight lipped on the identities of those struggling to declare themselves fit for the visit of Grimsby.
Amid a busy fixture schedule, he is loath to risk any of his players, although will make a late call on who is to start against the Mariners.
Definitely missing is Jack Whatmough, who remains sidelined with a hamstring problem.
Curtis Main is the other definite absentee.
Former Pompey favourite Ben Davies is expected to be on the bench for Grimsby.
Zac Mills is currently winning the right-back battle to keep the veteran out of the side.
But Davies is likely to be among the substitutes for his Fratton Park return.
Manager Marcus Bignot is weighing up retaining the side which won 3-0 at Leyton Orient at the weekend.
Gavin Gunning is once again sidelined with the concussion he collected at Wycombe, but Chris Clements may return after missing the Brisbane Road trip through illness.