The main event at UFC 178 was supposed to be a rematch between light heavyweight champion Jon Jones and Alexander Gustafsson, but an injury caused Gustafsson to back out. Daniel Cormier stepped in but then Jones injured his knee and needed surgery.

Now, lightweights Eddie Alvarez and Donald “Cowboy” Cerrone are in the spotlight at the MGM Grand Garden Arena, enhancing a card that features a title fight between flyweight champ Demetrious “Mighty Mouse” Johnson and Chris “Kamikaze” Cariaso, Conor McGregor vs. Dustin Poirier, Dominick Cruz taking on Takeya Mizugaki and Amanda Nunes fighting Cat Zingano. Recent UFC signee Alvarez and Cerrone seem to be creating buzz despite their last-minute matchup. The former gets his first chance to prove himself in the UFC while the latter brings crowd-favorite excitement and unpredictability. A win will place one of them in serious contention for a championship fight.

Meanwhile, Cariaso’s profile would get a serious jolt with a victory against Johnson, who has held the flyweight title since UFC introduced it back in 2012. Many observers consider Johnson to be one of the best pound-for-pound fighters in mixed martial arts, and, although he’s heavily favored, a crowd will always rise to its feet when an underdog such as Cariaso demonstrates heart in the Octagon.

MGM Grand, 9 p.m. Sept. 27, starting at $75 plus tax and fee. 800.745.3000 Ticketmaster