Fame And Glory is to be tried in headgear for what could be the decorated stayer's final start at next month's Breeders' Cup.
Last year's Ascot Gold Cup winner, who also has an Irish Derby and a Coronation Cup on his CV, will be one of nine runners for Aidan O'Brien at Santa Anita in just a week and a half's time.
O'Brien felt Fame And Glory's attitude could be called into question when he finished only fifth behind Rite Of Passage on Champions Day, and will test him on dirt for the first time in the Breeders' Cup Marathon.
"We are taking a bit of a chance I suppose," he said.
"He's got a little bit clever - he handles fast ground but he's a little bit older and wiser now and when the going gets tough he's very happy to curl up and not to try very hard.
"He's in good shape, came out of Ascot well and just curled up on the very bad ground. We'll probably run him in a visor.
"The dirt will be the interesting part, it's probably an unknown."
On potential retirement for the six-year-old, who is part-owned by Jim Hay as well as the Coolmore partnership, O'Brien said: "I think it's very possible. Obviously nothing has been decided but it's definitely a possibility."
Excelebration, now the joint-second highest rated horse in the world on a mark of 130 according to British Horseracing Authority handicapper Phil Smith, will aim to build on his scintillating Queen Elizabeth II Stakes victory in the Breeders' Cup Mile.
"He's in good form and I hope he travels there well," said O'Brien.
"We think he's a very exceptional horse. He's getting quicker and stronger and has progressed very well.
"He has top form in every kind of ground, I don't think ground is important to him.
"I'm not sure if he'll run again after America, it's not a decision for me really."
O'Brien has landed the Breeders' Cup Turf three times and will saddle both Treasure Beach and the returning champion St Nicholas Abbey.
O'Brien said: "St Nicholas Abbey is a fast ground horse really and Treasure Beach has been progressing - his last run was his best run - and we think he has progressed again since then."
The well-travelled Up takes in the Filly & Mare Turf with Starspangledbanner pencilled in for Friday's Mercury Stakes at Dundalk ahead of the Turf Sprint.
"We think a mile and a quarter is (Up's) best trip and she likes that quick ground, which she doesn't get much of here," he said.
Completing the team are three two-year-olds.
Infanta Branca should make the cut for the Juvenile Fillies' Turf, having finished fourth to stablemate, and Juvenile Turf-bound Lines Of Battle in a Listed event at Dundalk earlier this month.
George Vancouver, who was second to Reckless Abandon in the Prix Morny and third to Dawn Approach in the Dewhurst Stakes, joins Lines Of Battle in a bid to follow up Wrote's victory in the same race 12 months ago.
"We think the trip will suit (Infanta Branca) and she loves the fast ground as well," said the Ballydoyle trainer.
"She had a long break and had her first run back at Dundalk.
"We were very happy with her and think she has progressed since then.
"Lines of Battle won the Listed race the filly ran in and we think a mile will suit him.
"George Vancouver will have to be ridden to get the mile but fast ground is a big factor.
"The ground was a bit slow in the Dewhurst and obviously he's a typical Henrythenavigator and loves the fast ground."
O'Brien confirmed his son Joseph would ride as many of the runners as he could manage the weight for, with Ryan Moore on standby.