The Prix de l'Arc de Triomphe remains a possible target for Curlin although trainer Steve Asmussen has warned that connections 'can't get ahead' of themselves.
Officially the best horse in the world, Curlin has done all his racing so far on dirt, winning the Preakness before adding the Breeders' Cup Classic and the Dubai World Cup to his growing list of honours.
But following a pleasing workout on turf at Churchill Downs on Tuesday, Asmussen said it was all systems go for a trial race on the grass at either Arlington or Belmont on July 12.
"The way he's going I think he'll run over anything, any type of surface," he told the Racing Post. "It went how we hoped it would when when first made these plans.
"The main thing was that Robby (Alborado) loved how he felt."
Curlin returned to winning action at Churchill Downs just over a fortnight ago and if he comes through his Arc 'trial' he could be shipped to Europe sooner, rather than later.
"First he has to establish his level of quality on turf," added Asmussen. "We can't get ahead of ourselves. A nice work is not a graded stakes.
"I think getting him over there and getting him used to going right handed is the biggest obstacle we face."

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