Captain Sam Warburton will miss the game through suspension, while prop Adam Jones has a calf muscle injury after both players exited the agonising semi-final loss to France inside 20 minutes.
Paul James can expect to replace Jones, with Ryan Jones probably starting in the back row at number eight and Toby Faletau being handed the number seven shirt.
Warburton has started serving a three-week ban following his red card when he committed what was deemed a dangerous tip tackle on France wing Vincent Clerc.
Warburton admitted the offence at a disciplinary hearing in Auckland, when evidence was presented by the player, Gatland and Warburton's legal representative Aaron Lloyd.
Independent judicial officer, England's Christopher Quinlan QC, concluded that the offence was mid-range on the scale of seriousness, which has an entry point of six weeks.
He found that there were no aggravating features and there were compelling mitigating features, including the player's admission, outstanding character and disciplinary record and remorse, which saw the suspension cut in half.
Warburton is sidelined until November 7, with no appeal thought likely to me made by the Welsh Rugby Union.
"Obviously, I am very disappointed," Warburton said.
"But all my attention and focus now goes towards the players playing on Friday and supporting them the best I can."
Victory for Wales on Friday would match their best World Cup performance of third at the inaugural tournament 24 years ago. On that occasion they beat Australia in Rotorua.
And Wales' exciting crop of young players will have another opportunity to show a world audience their exciting collective ability that has been a feature of this World Cup.
Gatland added: "We have some young players that have come on in the last 12 months and have really developed.
"The biggest thing for us as a coaching team is that we have had the players since June, and that makes a difference to the way we have prepared and the way we have performed."
Wing Shane Williams, meanwhile, could make his farewell appearance for Wales in what would be an 86th Test match outing, having indicated on several previous occasions he would step down from international rugby post-World Cup.
The 34-year-old has made no definitive announcement, though, and it remains to be seen what he will decide.
"I haven't seen a game like it before," said Williams, reflecting on Wales' 9-8 loss to France. "We were shattered by half-time because of the effort.
"To not concede a try with only 14 men against a very potent French attack was a tremendous effort. I'm just devastated for the guys.
"The worst thing is that I thought we deserved so much more because we gave our all for 80 minutes."
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