Port Adelaide coach Ken Hinkley concedes the AFL career of his captain Tom Jonas has likely been ended by a calf injury.
Jonas damaged a calf muscle in the last minute of Port's training on Thursday and has been replaced by Trent McKenzie for Saturday night's qualifying final against the Brisbane Lions.
Jonas had announced he will retire at the end of the season and the injury is set to rule him out of the finals.
"We haven't got all the information back yet on scans and details," Hinkley told reporters on Friday at Adelaide Airport.
"But it looked like a significant calf injury which will put Tom right behind the eight ball to make some impact later on."
McKenzie hasn't played since suffering a knee injury on August 5.
"It's amazing the timing with what happened with Tom at training, so Trent was a significant in for us this week," Hinkley said.
Ruckman Scott Lycett (knee) and key forward Todd Marshall (hip) also return to the Power side after recovering from injury, while Hinkley confirmed former skipper Travis Boak will be the substitute after being dropped from the starting 22.
Brisbane and Port both won 17 games in the home-and-away season, with the Lions earning home-ground advantage because of a greater percentage.
Chris Fagan's Brisbane side are unbeaten in a dozen games at the Gabba this season but Hinkley rejected the underdog tag placed on Port.
"We don't feel like we're an underdog," he said.
"We have qualified equal second, people forget that we won 17 games for the year - that's a mighty effort by any team.
"We go up there full of confidence and knowing that our capability is one that can challenge any team in this competition.
"We have had seven games away this year that we have won.
"Those things (home ground) are not that big an influence once the game starts.
"It's the team who comes out and plays with the most composure and calmness in their game that will end up on top."
Hinkley had no doubt the Gabba clash would follow the formula of Collingwood's gruelling qualifying win over Melbourne on Thursday night.
"I expect the game will be a tough hard game like last night's and probably go right to the wire," he said.
"I just have great admiration for what (Brisbane) are and who Fages is and the way he coaches their team.
"They're a brutally tough team who you're going to have to play for a full four quarters to win."