NEW YORK (AP) -- Whenever Canelo Alvarez or Gennady Golovkin are ready to get back to business in the middleweight division, Danny Jacobs wants to be there waiting.
If he wins Saturday, he'd be waiting with a belt around his waist.
Jacobs meets Sergiy Derevyanchenko inside the Theater at Madison Square Garden, with the winner taking the IBF's vacant version of the 160-pound title.
There's been a flurry of changes within the division lately, with Alvarez owning half of the four major titles after edging longtime champion Golovkin last month in their rematch. Demetrius Andrade won the other belt last week, and Jacobs (34-2, 29 KOs) can put his name on the list of champions.
The 31-year-old from Brooklyn fell just short last year against Golovkin, who hasn't announced plans for his return from his first loss. And Jacobs would love a first chance at Alvarez, who is challenging for a 168-pound title in his next fight but is expected to return to middleweight afterward.
''Many believe and I'm one of them that he beat Gennady Golovkin in this building, and if that's the case I believe you have every right to call him the best middleweight in the world,'' said Eddie Hearn, Jacobs' promoter. ''But on Saturday he has a chance to do that and to move forward to those super fights, those other defining fights that could be out there: a Golovkin rematch, a Canelo fight, a unification fight with Andrade. These are the nights that lay ahead for Danny Jacobs and I know what it means to him to be victorious on Saturday night.''
It would mean getting by an opponent he knows well. Jacobs and Derevyanchenko (12-0, 10 KOs) have sparred together and both trained under Andre Rozier, who will remain with Jacobs for the HBO-televised bout. Gary Stark Sr., whom Jacobs has also worked with, is training the Ukrainian for the fight.
''So to see these guys on the opposite side of the ring come fight night, it's going to be bittersweet,'' Jacobs said. ''We all knew each other for a very, very long time, so it's almost as if we're like family. But this is why we do it, for the love of the sport.''
And for opportunities like Saturday, which have eluded the 32-year-old Derevyanchenko. A decorated amateur who had more than 400 fights, he's had trouble finding work as a professional. Even Golovkin wasn't interested in taking a fight with him when the first date for the Alvarez rematch had to be scrapped because of the Mexican's positive drug test. Derevyanchenko was the IBF's mandatory challenger, but Golovkin didn't pursue a bout so he could wait for Alvarez to be reinstated. The organization backed a challenge from Derevyanchenko's management, forcing the title off Golovkin and giving the Ukrainian a chance to win it in his first title shot.
''This guy's had a rough road as a pro. Almost impossible to get him fights,'' promoter Lou DiBella said. ''We had to pull a lot of political machinations and legal machinations and all sorts of stuff to get him to this position, and I'm thrilled that we were able to.
''He had to sit and wait out his opportunity as the No. 1 mandatory. He couldn't make himself unavailable so he had to be relatively inactive and then all of a sudden Danny Jacobs was the next guy in the rankings, and all of a sudden there's a huge fight for Sergiy, the fight he's been waiting his whole life for.''
It comes at the end of a card that also includes Puerto Rico's Alberto Machado defending a 130-pound title against Yuandale Evans, and a rematch of Heather Hardy's 2016 victory over Shelly Vincent.
Derevyanchenko predicted the main event would be a ''big war.'' Jacobs, a survivor of a rare form of bone cancer, is ready for it.
''I fight with glory, I fight with guts, I fight with skill,'' Jacobs said.