An inside barrier has convinced trainer Anthony Cummings to run blue blood mare Rule The River at midweek level.

Rule The River is nominated for a fillies and mares race at Rosehill on Saturday, but she is favourite to make it back-to-back wins in the TAB.com.au Handicap at Warwick Farm on Wednesday.

"Because she's drawn close to the rail at Warwick Farm it makes the decision a bit easier to run there," Cummings said.

"We scratched her off a wide draw last week and Wednesday's race seems to fit in best for her."

Rule The River will launch her bid from gate two over 1000m at Warwick Farm and Cummings has engaged apprentice Regan Bayliss to off-set her 58kg.

"She's not huge, she's got a nice deep girth but with two kilos off her back it probably makes a difference to her chances," Cummings said.

Rule The River holds favouritism over Canberra mares Highly Geared and Karakuchi and there will be few better-bred horses racing at Warwick Farm on Wednesday.

Owned by Gerry Harvey, Rule The River is a member of one of the studbook's most distinguished families, counting former top Hong Kong sprinter One World as a half-brother.

And Cummings says he is no hurry to challenge her breeding page after taking a conservative approach that has kept Rule The River to just four starts in 18 months of racing.

"Gerry's a very patient owner and it allows us to be patient with her in the stable," Cummings said.

"While she's learning she's pretty comfortable at this sort of trip so there's no need to test her beyond her limit."

Rule The River had her first start since January when she scooted along the inside to beat Festivity at Canterbury on November 7.

"I expected her to run well first-up and with Festivity winning impressively at Rosehill since then it makes the Canterbury win look even better," Cummings said.