By Keith Idec

Gary “Spike” O’Sullivan has agreed to Golden Boy Promotions’ offer to challenge Gennady Golovkin on May 5.

According to O’Sullivan’s Twitter message Wednesday, all that’s left to cement him replacing the suspended Canelo Alvarez is for Golovkin to agree to the fight. O’Sullivan would be a huge underdog against Golovkin if the IBF/IBO/WBA/WBC middleweight champion accepts O’Sullivan as Alvarez’s replacement.

Former WBA super welterweight champ Demetrius Andrade (25-0, 16 KOs) and Sergiy Derevyanchenko (12-1, 10 KOs), the mandatory challenger for Golovkin’s IBF title, also are among the fighters who have expressed willingness to fight Golovkin on short notice. Ireland’s O’Sullivan (27-2, 19 KOs) is widely viewed as an easier opponent for Golovkin than Andrade or Derevyanchenko, but O’Sullivan is co-promoted by Golden Boy Promotions, which also handles Alvarez.

“My job as a professional boxer is to say yes to fights and to make sure I’m ready for them,” O’Sullivan wrote on Twitter. “After that it goes to the people who negotiate the deals to make fights possible. I’ve said yes to fighting GGG, I’ve been training nonstop since my last fight and now I’m waiting to see if it can be agreed, just like you. I trust my team to do what’s right for me, one way or the other.

“As soon as I know what’s going on I’ll tell you. If I get the opportunity to go in against the best, I won’t let you down. I truly believe it is my destiny to become the world champion.”

Golovkin still wants to fight May 5 because he has been training for more than a month for his high-profile rematch against Alvarez. Mexico’s Alvarez withdrew from their HBO Pay-Per-View bout Tuesday because he and his team expect the Nevada State Athletic Commission to extend his temporary suspension April 18 for failing two Voluntary Anti-Doping Association tests for clenbuterol in February.

Depending on the length of Alvarez’s suspension, his rematch against Golovkin could be rescheduled for as soon as September 15. Alvarez and Golovkin have both stated that they still want their rematch to take place as soon as possible.

With an eight-figure purse for facing Alvarez at stake, Golovkin isn’t likely to take too threatening of a fight before he boxes Alvarez again.

The 33-year-old O’Sullivan most recently scored a seventh-round knockout of American Antoine Douglas (22-2-1, 16 KOs). HBO broadcast that bout December 16 from Place Bell in Laval, Quebec, Canada.

O’Sullivan has lost only to WBO middleweight champion Billy Joe Saunders (26-0, 12 KOs) and super middleweight contender Chris Eubank Jr. (26-2, 20 KOs).

Saunders defeated O’Sullivan by unanimous decision in a 12-round, non-title fight in July 2013 in London. Eubank beat O’Sullivan by technical knockout when O’Sullivan declined to continue beyond the seventh round of an entertaining fight in December 2015 in London.

Whoever Golovkin fights May 5, the card is expected to be held at MGM Grand Garden Arena in Las Vegas. Nearby T-Mobile Arena would’ve been the site for the Alvarez-Golovkin rematch had it taken place May 5.

Alvarez (49-1-2, 34 KOs) and Golovkin (37-0-1, 33 KOs) fought to a controversial 12-round draw September 16 at T-Mobile Arena.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.