Chris Waller won't be a casual observer at Churchill Downs this weekend for the Kentucky Derby. It's not his style.

Sydney's premier trainer flew to the United States on Wednesday for what could best be described as a working holiday, or in racing manager Charlie Duckworth's view - a fact-finding mission.

Although Waller could warrant a spell after a hectic autumn dominated by Winx's all-conquering exploits, he will be having a brainstorming session with Bob Baffert, trainer of the world's best horse, Arrogate.

"Chris is not very casual," Duckworth said.

"He'll be linking up with Bob and no doubt picking his mind on how we can improve things and do things differently."

Waller and Baffert - a four-time Kentucky Derby winner - met at the Longines Horse of the Year awards in London in January when the American took home the supreme award and Winx was judged the world's best horse of turf.

"It's very similar to when he went to visit Aidan O'Brien at Ballydoyle (Ireland) ," Duckworth said.

"Chris changed and tweaked a few things around.

"He's always looking for an extra two and three per cent to improve the way he trains, and the way he can get our horses to perform."

Baffert, 64, the trainer of four Kentucky Derby winners including 2015 triple crown winner American Pharoah, does not have a runner this year.

Duckworth said there were obvious barriers to Waller one day targeting a race like the Kentucky Derby.

"The breeding makes it harder for us," he said.

"We'd have to send a two-year-old to run in the northern hemisphere against their three-year-olds.

"It's also on a dirt track and that makes it harder because there's no dirt tracks in Australia. Having said that I'm scared to rule out too many things out with him."