Gardiner was set to play his first game for Marist since April. But on Thursday co-coach Ross Kennedy said he had been ruled out of the preliminary final due to a calf injury.
Marist will still be boosted by the availability of Crusader Tahlor Cahill.
Cahill, a lock, has played for the club regularly this season but has not featured since the win over Burnside on June 22.
Marist take on a resurgent Linwood who recorded their second upset win in a row in the semi-final, beating HSOB 30-27 thanks to a last-second penalty from Josh Jennings.
The other preliminary final will see Canterbury University host Sydenham – the top two sides after the regular season.
Kennedy said his side would be wary of the threat posed by Linwood.
“They’ve built good momentum in the last few weeks and they’re a dangerous team with many powerful ball runners.
“It was about 43 to 30-something (47-36) when we played them earlier this year, so it was a high-scoring affair.”
At this stage of the competition last year, Linwood bowed out at the hands of Marist, but head coach Brendan Nolan said they wouldn’t take any extra motivation from that result.
“We’ve got a lot of respect for them, I think it goes both ways.
“We just look at what’s happening in front of us, not so much what’s going on behind, in the past.”
The winners will play in the final next Saturday at Rugby Park.
Metro rugby preliminary finals (2.45pm Sat)
Plate final (2.45pm Sat)
Semi-final results
