After a season in which the former Wellington and Hurricanes player struggled for game time at the Blues, Weepu will be forced to watch the Premiership showpiece at AMI Stadium in Christchurch from the relative comfort of his couch.
He and Charlie Faumuina were made available by All Blacks' management following Saturday's drawn Bledisloe Cup test in Brisbane, but only prop Faumuina will receive the nod.
Pivac, who will announce his squad on Thursday, said the decision to select Alby Mathewson as his No 9 was made for the "good of the team".
"It's very simple - we hadn't planned to use any All Blacks, to be honest," he said.
Faumuina, who made his first start for the All Blacks in Brisbane, would be picked only because Ofa Tu'ungafasi had a broken thumb, Pivac said.
"The halfback one, we've been doing a lot of work in the last six to eight weeks and it's all based around what we do at eight, nine, 10 and 12. We just think it's a big ask [Weepu] coming in and trying to control the game for us. Alby has been doing a pretty good job, he has been playing a lot of 80-minute games. We're putting the team first and that's the decision that I've made."
Pivac's decision is interesting in light of his back-up options at No 9. Scott Patterson was to fulfil the role in last weekend's semifinal win over Wellington but injured his back in the warm-up and won't be named on Thursday.
Instead, Ponsonby's Wayne Ngaluafe, a former New Zealand Under-19 representative who hasn't played all year due to a knee injury, is likely to get the nod, leaving no room for Weepu, who has played 66 tests.
Canterbury, the defending champions who thrashed Auckland in round two of the competition, are allowed to select All Black props Wyatt Crockett and Ben Franks for the final. Crockett scored two tries in Canterbury's extra time semifinal win over Taranaki last weekend, with Franks yet to play for them this season.
Pivac said lock Ali Williams, who is recovering from a back injury, is a chance to play in what is likely to be captain Daniel Braid's last match for the union.
He said of flanker Braid: "He's been a great player for Auckland. You've just got to look at Daniel, he's not the biggest player on the field but he certainly has a big ticker and he goes for 80 minutes."
