Lightweights Michael Chiesa and Francisco Trinaldo will square off this May at UFC 173.

Officials announced the bout for the May 24 card from Las Vegas. In the main event, Chris Weidman defends his middleweight title against Lyoto Machida.

Chiesa (10-1) rebounded from his first career loss by submitting Colton Smith in a battle of former Ultimate Fighter winners. He lost to Jorge Masvidal last year, snapping a nine-fight win streak.

Trinaldo (14-3) has won four of six UFC fights, besting Jesse Ronson in his most recent bout. He is 3-1 in his last four, with the lone loss to Piotr Hallmann.

Below is a current list of fights announced:

UFC Middleweight Championship
Chris Weidman (c) vs. Lyoto Machida

Lightweight: Jamie Varner vs. James Krause

Bantamweight: Chris Holdsworth vs. Kyung-Ho Kang

Featherweight: Sam Sicilia vs. Doo Ho Choi

Bantamweight: TJ Dillashaw vs. Takeya Mizugaki

Lightweight: Al Iaquinta vs. Mitch Clarke

Lightweight: Michael Chiesa vs. Francisco Trinaldo