Kenny Jackett has confirmed star striker Omar Bogle will miss the trip to Sunderland - but he could make a surprise return before the end of the season.
Earlier this week it was feared he would miss the rest of the campaign, with Portsmouth battling Sunderland, Charlton and Barnsley for an automatic promotion spot, due to swelling on his knee and ankle.
Bogle, on loan from Cardiff City, missed the Easter Monday win over Coventry City and will definitely miss the trip to the Stadium of Light on Saturday (KO 3pm).
That is a boost for Sunderland but Jackett has revealed the 25-year-old striker could still feature before the campaign having responded well to treatment.
The striker joined Pompey at the turn of the year and has since scored four goals in 12 games, with Portsmouth third in League One, two points clear of Sunderland in fourth.
Jackett told the Portsmouth News: “(Bogle’s injury) is improving and improving quickly.
“He obviously won’t be fit for Saturday. We will see if he can make next week.
“Time is possibly against him but the early signs of the injury are better and are good, which is great for us.
“He has just moved off the crutches now. He is at Portsmouth having his rehab.”
Portsmouth travel to the North East four weeks after their Checkatrade Trophy final success on penalties against the Black Cats.
Ahead of the game, Jackett is expecting a “huge” atmosphere on Wearside with another bumper crowd expected.
And he has urged his promotion-chasing squad to be calm and focused.
He added: “The players have applied themselves well all season. We need to be calm and focus on our own performance.
“It’s a big game that we’re all looking forward to. Sunderland are a very big club and I expect a huge atmosphere on Saturday.”