Gray, 21, was a surprise omission from the team that crushed Adelaide last weekend and it's since been revealed he was ineligible for selection because of a club-imposed ban.
The crafty goalkicker broke curfew on Port Adelaide's player-funded trip to the Gold Coast before Christmas, arriving back to the hotel 20 minutes late after a dinner.
He was made available for next weekend's clash with West Coast, but is now likely to miss while he recovers from surgery.
Veteran Josh Carr (calf) is also expected to sit out the game, but Travis Boak (glute), Dean Brogan (corked quad) and rookie Cameron Hitchcock (sprained AC joint) should all be fit to play.
Ex-Carlton and Collingwood utility Cameron Cloke (shoulder) may also receive a call up along with experienced duo Warren Tredrea and Chad Cornes.
The Power unveiled seven debutants in the 56-point win over the Crows, including promising defender Jackson Trengove.
Trengove, 19, has been touted as a potential replacement for retired ruckman Brendon Lade, but the athletic 197cm Victorian said he was just focused on retaining his place in the side.
"We've got Chad Cornes coming back next week who'll probably slot straight back into our backline, so whether that sees me go out of the side I don't know," Trengove said on Wednesday.
"I'll just keep training hard and if that sees me on the park during the year I'll be happy. I haven't got very high expectations, so I'll probably go back and play some SANFL footy."
If Trengove holds his spot he'll come up against West Coast sensation Nic Naitanui when the two sides meet at Subiaco next week.
The two were both drafted in 2008, but never crossed paths as juniors because of Trengove's horrific hamstring/knee injury.
Trengove admitted he enjoyed watching Naitanui's four-goal heroics against Essendon last weekend.
"Nic's a fantastic player. There's been a lot of hype about him and he's delivering at the moment," he said.
"He's grouse to watch. If I end up playing on him I just hope he doesn't jump all over me like he does everyone else."
The Power surprised most punters with their committed performance against the fancied Crows, but Trengove insisted the hard work was still there to be done.
"We're not right there now and we've got to keep focusing on the next task ahead. If we can do that then we'll push a few teams," he said.
"The boys are pretty down to earth at the moment. We won the first NAB Cup game, but it doesn't really mean a great deal to us. We've got a lot to prove to the rest of the competition, so we'll keep working on that."
