Johnny Murtagh is likely to team up with Ursa Major as he seeks to win the Ladbrokes St Leger for the first time at Doncaster on Saturday.
The Irish jockey is set to get the leg up on the Tommy Carmody-trained colt after connections confirmed plans to go for the world's oldest Classic.
The son of Galileo also holds an entry in the Gain Horse Feeds Irish St Leger at the Curragh the same day, but owner Andrew Tinkler will instead rely on Royal Diamond in that particular contest.
"We've made the decision to head for Doncaster (with Ursa Major) and let him take his chance against his own age group," said Tinkler's racing manager, Tim Jones.
"He's done absolutely nothing wrong up until now and appears to be very progressive.
"He did his final piece of work this morning in advance of the weekend. It all went very well, so it's all systems go for Doncaster.
"I think Johnny will ride him."
Ursa Major has made great strides since making his racecourse debut in March.
After winning one and finishing second twice in his first three starts, he won two handicaps in good style before winning the Group Three Irish St Leger Trial at the Curragh last month.
Conditions on Town Moor have dried out slightly following a dry and breezy day.
However, some rain is forecast for the start of the four-day St Leger Festival on Wednesday before dry weather returns to dominate the rest of the week.
"We have dried up a little bit during the day and it's been quite breezy. The ground is good to firm, good in places," said Doncaster clerk of the course Jon Pullin.
"We are forecast around five millimetres of rain tomorrow. Thursday onwards should be dry with temperatures between 18C and 20C.
"We finished watering on Monday lunchtime once the forecast indicated there was rain. There are no plans to water any further."