Unified junior welterweight world champion Terence Crawford, one of boxing's top fighters pound for pound, is due back in the ring to make his fifth title defense on May 20, Top Rank promoter Bob Arum told ESPN on Wednesday.

Arum, who said May 20 is the date HBO is holding for Crawford (30-0, 21 KOs), said he hopes to have the 29-year-old fight once again in his hometown of Omaha, Nebraska, where he is a big draw.

Arum said while no opponent has been signed yet there are two candidates in the running: 29-year-old San Diego contender Antonio Orozco (25-0, 16 KOs), one of Crawford's mandatory challengers, and southpaw Felix Diaz (19-1, 9 KOs), 33, a 2008 Olympic gold medalist from the Dominican Republic.

Orozco, who would be a massive underdog despite his spotless record, had a Dec. 16 bout against Fidel Maldonado Jr. canceled the day before the fight because Orozco was hospitalized due to dehydration from trying to make weight. Golden Boy Promotions, Orozco's promoter, has shown little desire in matching him with Crawford. It turned down the shot in December.

Diaz, who is far more highly regarded than Orozco, suffered his lone defeat by controversial 12-round majority decision to former world titleholder Lamont Peterson in October 2015 fighting on his home turf just outside Washington, D.C., in Fairfax, Virginia. Diaz has won two in a row since, including an impressive 10-round decision victory against then-unbeaten rising contender Sammy Vasquez Jr. in July.

Arum has a distinct opinion on which match he wants to make.

"I want to do the fight with Felix Diaz. That's the best fight for us to make," said Arum, who added that some of his closest advisers in the company are against it. "Lou DiBella (Diaz's promoter) calls me every day about it. That's the fight I want to make."

DiBella said he and Arum have talked money and they are not far apart.

"I'm about to call him again today," DiBella told ESPN. "My guy is ready, willing and able to go May 20 and Omaha would be fine with us. I know there are people within Top Rank that like the fight very much and also I know there are people within Top Rank that don't. That's the way it usually is with a really good, competitive fight. I've been in this business a long time and I gave Bob a number that's fair and he didn't balk. I'm going to continue calling him every day until we hopefully close the deal."

Crawford unified two 140-pound world titles in July with a one-sided decision win against then-undefeated Viktor Postol in perhaps the best win of his career and then followed with a one-sided eighth-round destruction of overmatched and overweight John Molina Jr. on Dec. 10.

"I know how good Terence Crawford is and I don't think for a second he is scared of anybody," DiBella said. "But that being said, given his recent fight the fans want him to be challenged and there's no question Felix Diaz brings a challenge. There are guys out there screaming for a fight with Manny Pacquiao or to get Floyd Mayweather out of retirement, but there aren't guys screaming they want to fight Terence Crawford. But Felix Diaz wants Terence Crawford. He believes Crawford is his measuring stick to see how good he is. He thinks, 'You're good, the public thinks you're good, so I want to fight you.'"