With no return date set for UFC champion Robert Whittaker, the rest of the middleweight division will continue to jockey for position in his absence.

On Thursday, officials announced that Ronaldo “Jacare” Souza and Kelvin Gastelum will fight at UFC 224, which takes place at the Jeunesse Arena in Rio de Janeiro on May 12.

This will be Souza’s second booking of 2018. In January, he needed less than a round to defeat Derek Brunson by TKO in the main event of UFC on FOX 27. It was the second time that “Jacare” finished Brunson with strikes. The 38-year-old Brazilian owns an 8-2 UFC record, with his only losses coming at the hands of Whittaker and potential No. 1 contender Yoel Romero.

During a recent appearance on The MMA Hour, Romero claimed that UFC president Dana White told him he is next in line for a shot at Whittaker’s title.

Gastelum, 26, is 4-1 with one no-contest competing at 185 pounds. The Ultimate Fighter 17 winner bounced back from a loss to Chris Weidman in spectacular fashion, knocking out former middleweight champion Michael Bisping in 2:30 to close out UFC Shanghai last November.

Also scheduled for the show is a middleweight matchup between Brazilian legends Vitor Belfort and Lyoto Machida.

See the updated UFC 224 card below:

Vitor Belfort vs. Lyoto Machida

Ronaldo “Jacare” Souza vs. Kelvin Gastelum

Davi Ramos vs. Nick Hein

Alberto Mina vs. Ramazan Emeev

Alexey Oleynik vs. Junior Albini

Cezar Ferreira vs. Karl Roberson