Prince Of Penzance's managing owner John Richards insists Michelle Payne's fitness is the only reason she is not riding the Melbourne Cup winner first-up.

The Darren Weir-trained stayer is scheduled to return in the Group One Memsie Stakes at Caulfield on August 27.

Richards said the decision to take Payne off was made in consultation with Weir and the ownership group.

"The decision that we've made is not to put Michelle on in the Memsie Stakes because we believe she's not ready to ride at that level," Richards told Melbourne radio station RSN927.

Payne hasn't ridden since a race fall at Mildura in May.

She underwent surgery on her pancreas and spent two weeks in hospital before heading to her father Paddy's home at Ballarat.

Payne has been riding trackwork at Ballarat in recent weeks and rode Prince Of Penzance in a trial at Casterton on Monday.

She has ridden Prince Of Penzance in 24 of his 25 starts and in all the gelding's seven wins.

"Michelle and the owners have had a wonderful relationship as was evidenced last year," Richards said.

Richards has not ruled out Payne being reunited with Prince Of Penzance in the future, but also says in his opinion she should retire following her latest injury.

"That's my personal opinion, not hers," he said.

Richards said a decision who would ride Prince Of Penzance first-up would be made in consultation with Weir.

"The choice of jockey is terribly important and the horse runs well for Michelle," he said.

"The horse also deserves a jockey that is fully fit and also race fit, not just physically fit, and riding competitively at A grade level."

Weir said the decision not to put Payne on Prince Of Penzance in the Memsie was made by the owners.

"If Michelle can get back to riding in good form down the track they'll probably consider her to ride him later on," Weir said.

"I think she's getting pretty close to race riding again but you need to go around a few times to get your eye back in."