In the absence of champion filly Songbird, Rachel's Valentina is the early favourite to emulate her mother in the Kentucky Oaks.

The unbeaten Songbird has been ruled out of Friday's Classic because of a low-grade fever for which she is being treated.

Rachel's Valentina is a daughter of 2009 Horse of the Year Rachel Alexandra who won the Oaks before beating the males in the Preakness Stakes, the Haskell International and the Woodward Stakes.

Bernardini, Rachel's Valentina's sire, won the 2006 Preakness and Travers Stakes to be crowned that season's champion three-year-old colt.

Trained by Todd Pletcher and to be ridden by John Velazquez, Rachel's Valentina is at 7-2 to win from barrier 11 of 14.

Rachel's Valentina was second in her past two outings. She finished 5-3/4 lengths behind Songbird in the Breeders' Cup Juvenile Fillies, her lone defeat in three races last season.

She was only a neck behind Weep No More in her return, the Ashland Stakes at Keeneland last month.

"It was one of those frustrating losses but you have to be very pleased and proud of her effort," Pletcher said.

"It was very encouraging that she's come back as a top class filly."

Pletcher, a three-time Oaks winner, also sends out Mo d'Amour, a 30-1 long shot in post 7.

Weep No More, three for three this year following the Ashland victory, is the equal second choice at 9-2 alongside Ashland third Cathryn Sophia.