UFC president Dana White originally announced the bout for July 29, but sources said it the fight was actually booked for the Aug. 18 card. When the promotion pulled the plug on the Seattle card, McMann-Vieira was moved to Sept. 9.
McMann (11-3) won three in a row since losing to future champion Amanda Nunes in 2015, including submissions over Alexis Davis and Gina Mazany. The one-time UFC title contender and Olympic medalist holds s 5-3 UFC record.
Vieira (8-0) scored decision wins in both of her UFC appearances, defeating Kelly Faszholz and Ashlee Evans-Smith. The Nova Uniao bantamweight finished five of her fix opponents before joining the UFC in 2016.
The UFC has yet to announce the main event for the pay-per-view card, which takes place at Edmonton’s Rogers Place.