The 26-year-old helped New Zealand claim a silver medal in the sevens tournament at the Rio Olympics last month.
She is in Dunedin promoting sevens but was not expected to front for Otago against Wellington in Porirua as she is registered with Bay of Plenty and has not played for Otago in four years.
However, Brazier needs some game time in the 15-man code to qualify for Black Ferns selection and she wanted to play for Otago, coach Duncan McEwan said.
"Basically we got a call from the NZRFU asking us if she could play for us," McEwan said.
"She wanted to play for Otago, so we supported her. It is a little disruptive for the team, as far as preparation goes and getting her up to speed and all that kind of stuff.
"But, at the same time, having her in our environment and the level of professionalism she brings ... will be quite valuable."
It will be a one-off appearance, though. Brazier will take leave before she is expected to join the Black Ferns camp.
Brazier, who made her provincial debut for Otago as a 15-year-old, will play at fullback. How much impact she can have on the game will depend on how much ball the Spirit can secure.
"She will certainly help us use any ball we have, that is for sure."
Brazier played 31 games for Otago from 2005 to 2012 before moving north to further her sevens career.
In other changes to the starting XV, Michaela Baker shifts from wing to second five-eighth. Regular centre Kilisitina Moata’ane is out injured, so Greer Muir moves out one to centre.
Hannah Stolba drops to the bench to make way for Brazier and Georgina McCullough comes on to the right wing.
No8 Rachel Ovens returns to the run-on side with Maddi Finch dropping to the bench.
The Spirit is out of title contention after three consecutive losses.
Otago Spirit team
to play Wellington
Kelly Brazier, Georgina McCullough, Greer Muir, Michaela Baker, Renaye Flockton, Olivia Waldron, Megan Manson, Rachel Ovens, Georgia Mason, Angie Sisifa, Julia Gorinski, Annemieke van Vliet, Gemma Tuhega, Tegan Hollows, Kirsten Shalosky. Reserves: Paige Church, Eilis Doyle, Jess Kendall, Maddi Finch, Zoe Whatarau, Hannah Stolba, Kiana Wereta.