By Edward Chaykovsky, photo by Premier Boxing Champions

Promoter Eddie Hearn of Matchroom Sport is still working out the details to finalize a welterweight unification between his fighter, IBF welterweight champion Kell Brook (36-0, 25KOs), and WBO champion Jessie Vargas.

The fight is heading to a date in late August or September, but there have been some issues with getting the terms together for Brook. Vargas has already signed on for the fight.

One of the issues is getting a firm fight date, to ensure that it doesn't create a conflict with a potential middleweight fight between Gennady Golovkin and Chris Eubank Jr. - which Hearn is also finalizing up.

"There has been some understandable frustration in the delays in announcing Kell Brook's unification fight with WBO welterweight champion Jessie Vargas," Hearn told Daily Mail.

"The issues right now are very small. We are trying to get the right date in relation to the Eubank-Golovkin fight and we are also still discussing the US TV rights. I have to say the recent US dollar swing has not helped. But this fight will happen. And when it does Brook, the IBF champion, will underline that he is the best welterweight in the world."

Hearn took a good look at last week's welterweight war between WBA champion Keith Thurman and challenger Shawn Porter. Brook won a close decision over Porter in 2014 to win the IBF belt. Thurman also won a close decision over Porter - and Hearn is confident that Brook will beat either man - and WBC world champion Danny Garcia, too.

"I watched the Keith Thurman-Shawn Porter fight the other night and I know Kell is better. He beat Porter in his backyard and after the Vargas fight we will look to make a fight with Thurman or Danny Garcia. He will have all the belts before long," Hearn said.