Terry Flanagan will fight Maurice Hooker for the vacant WBO light-welterweight title on the same bill as Tyson Fury's comeback at the Manchester Arena on June 9.
The former world lightweight champion, 28, had been scheduled to fight undefeated American Hooker on April 14 on the undercard of Billy Joe Saunders' WBO middleweight title defence against Martin Murray, which was postponed until June 23.
"Winning this fight will prove that I'm a legitimate 140-pound fighter," Flanagan said. "I'll be looking to unify all of the belts later in the year. I'm looking for the likes of Mikey Garcia after I win.
"He is a very good unbeaten fighter, he fights on the back foot and looks to catch you from distance. I'm not looking past Hooker but I'm very confident I'll be able to deal with anything he throws at me."
Hooker, also 28, said of his British opponent: "He's weak and he's soft. He hasn't fought anybody. He fights little guys. I hit hard with both hands. He's never fought anyone with skills like me. He runs a lot. He does that real good. Power? He hasn't got any power. He pitty-pats.
"He holds a lot, he uses his forearm to the head. He does a lot of stuff dirty. I'm going to stop him and I'm going to show him who's the best at 140."