The UFC confirmed a bantamweight title defence by Renan Barao, who was to face No. 4 contender Eddie Wineland, is now off because Barao was injured during training.
Later Tuesday, the organization said that another fight already on the card would be bumped up to become the main event — Rashad Evans versus Dan Henderson.
Evans (17-3-1) is a former UFC light heavyweight champion while Henderson (29-9) had been on a path to score a title shot until he lost a split decision at UFC 157.
Other planned bouts include light-heavyweights Mauricio (Shogun) Rua against Antonio Rogerio Nogueira.
Alexis Davis of Port Colborne, Ont., will also face Rosi Sexton from Manchester, England, in the first ever UFC women's bantamweight bout in Canada.
Lightweight Mitch (Danger Zone) Clarke of Saskatoon will fight England's John (The One) Maguire and light-heavyweight Ryan (Big Deal) Jimmo of Edmonton by way of Saint John, N.B., will face Croatia's Igor Pokrajac.