Villiers Stakes winner Sky Boy has suffered an injury which rules him out of the Doncaster Mile.

The Anthony Cummings-trained four-year-old earned a place in the $3 million Doncaster Mile in April with his win in the Group Two Villiers Stakes in December.

Owner Think Big Stud says the gelding has a soft tissue injury which could sideline him for the rest of the year and has ruined plans to set him on a Melbourne Cup campaign.

"Sky Boy ... will unfortunately not be able to take up his ballot exempt entry into the Doncaster and may not be seen for the rest of 2019 after suffering a soft tissue training injury this week" Think Big said on Twitter.

Sky Boy had been a $26 chance for the Doncaster with triple Group One winner The Autumn Sun heading the TAB market at $4.

The gelding is by Pendragon out of Zazabelle, both trained by the late Bart Cummings for Think Big Stud's owner Dato Tan Chin Nam who died in October.

Among Dato Tan's big wins were four of Cummings' 12 Melbourne Cups with Zazabelle third in the race in 1999.