Ronnie Shields, trainer of top middleweight contender Jermall Charlo (26-0, 20 KOs), says his boxer was ready and willing to fight IBF, WBA, WBC, IBO champion Gennady Golovkin (37-0-1, 33 KOs) - but the World Boxing Council told them to wait.

Golovkin was scheduled to face Canelo Alvarez in a rematch on May 5th at the T-Mobile Arena in Las Vegas.

But last week, Canelo withdrew from the contest. The Mexican star was placed under a temporary suspension by the Nevada State Athletic Commission, because the boxer tested positive for clenbuterol in two separate drug tests taken in February. Canelo must appear at a hearing on April 18.

Golovkin still plans to fight on May 5, but in a voluntary defense.

Charlo is the mandatory challenger to Golovkin's WBC title.

"The thing about Jermall, he’s already the mandatory but since Golovkin and Canelo were supposed to fight in a rematch, they told us we had to wait until after that fight to fight for that belt. We didn’t want to sit back and wait a whole year before we got back in the ring, so we decided to take another fight before that to try to keep busy," Shields told On The Ropes Boxing Radio.

Charlo will fight Hugo Centeno for the WBC's interim-title at the Barclays Center in Brooklyn.

After that contest is over, Charlo will target his mandatory crack at Golovkin.

"Oh absolutely, he’s definitely in his prime and at his best right now. He presents a lot of problems for everybody in boxing right now who is in the middleweight division. All of these guys know it, everybody talks but when it’s time to put up, nobody puts up, everybody shuts up," Shields said.

"The only thing is to continue to train hard, continue to fight whoever they put in front of us and that’s all we can do. We’d like to fight more often if that’s possible. We already have another date for August, but we’re not looking past anyone. What we want is to continue to fight and continue to show people that Jermall Charlo is the best middleweight in the world."