Source: Claressa Shields to fight Savannah Marshall for undisputed middleweight championship in September

The Claressa Shields-Savannah Marshall fight for the undisputed middleweight championship is expected to take place either Sept. 3 or Sept. 10 in the United Kingdom, a source confirmed to ESPN.

This comes after Ben Shalom, the promoter for BOXXER, which is putting on the fight, told IFL TV on Thursday that both fighters have signed.

"We're ready to go," Shalom said. "... I can't wait."

While the fight is yet to be announced, a source with knowledge of the negotiation believes there isn't anything standing in the way of it getting done.

This comes a week after Shields said she would not fight Marshall in September because of potential training for her Professional Fighters League bout scheduled for November. But now, she is still expected to fight in the PFL later this year -- after the biggest fight she'll have in her boxing career.

Shields (12-0, 2 KOs) and Marshall (12-0, 10 KOs) both signed a multifight agreement in November 2021 with this fight particularly in mind.

Marshall, the WBO middleweight champion, gave Shields, the WBC, WBA and IBF middleweight champ, the only loss of her career in the professional or amateur boxing ranks when she defeated her in the preliminaries of the AIBA World Championships on May 14, 2012.

Now, more than a decade later, the two will fight again -- this time as professionals in one of the bigger fights in the history of women in the sport.

The fight was initially expected to happen in July, but an injury to Marshall pushed the potential date back a little over a month. Shields initially balked at the move, but has now agreed to take the fight.