According to promoter Ben Shalom, WBO middleweight champion Savannah Marshall recently had a 'small operation.'

As a result, the unexpected medical procedure will delay a planned unification with WBC, IBF, WBA champion Claressa Shields by 'four or five weeks.'

Shields is not very happy with the delay - for a fight that she's pushing to happen sooner than later.

The unification was initially targeted for the month of July. Due to Marshall's operation, the months of August or September seem more likely.

"Savannah had to have a small operation that unexpectedly required her to need a few weeks of recovery," Shalom said to Sky Sports.

"That meant, obviously, that July was too early, which means that we'll just go back four or five weeks. Hopefully Claressa is going to be sensible and accept that both of them need to be fit and ready for what is the biggest fight in both of their careers and one of the biggest fights in the sport."

Shields' longtime promoter, Dmitriy Salita, is crossing his fingers that everything can be wrapped up.

"Shields vs Marshall is a mega fight and a mega sporting event which can raise the level of women's sports. I certainly hope the fight can get finalized. Claressa is ready, all is confirmed from our side the ball is in Savannah's court, and we are waiting for confirmation from her team," Salita said.

Marshall handed Shields her only loss in a boxing ring - when the two women were amateurs. Shields was only 17-years-old at the time of the fight. The loss did not affect her future in the ring, as Shields became a two-time Olympic gold medal winner and also a three division world champion as a pro - with undisputed achievements at 154 and 160.