Palhares (14-3) has won six of his past seven fights, registering four submission victories during that span.
Belcher (17-6) will enter the bout riding a three-fight win streak. He began getting some attention as a 185-pound contender after his first-round stoppage of Jason MacDonald in September.
Palhares-Belcher is the most recent bout announced for the May 5 card.
Franklin McNeil covers mixed martial arts and boxing for ESPN.com. Follow him on Twitter at www.twitter.com/Franklin_McNeil