Rock of Gibraltar, Europe's leading miler, could end his career in the Breeders' Cup Classic, his trainer Aidan O'Brien said Tuesday.

O'Brien said that Rock of Gibraltar, a 3-year-old son of Danehill, was being seriously considered for the $4 million Classic. It would be his first race on dirt and his first at beyond a mile.

"He is by Danehill, who is by Danzig, and he has Bold Ruler influence on his dam's side, so there is quite a bit of American influence in his pedigree," O'Brien said from his training center in Ireland. "He hasn't been ruled out of either the Classic or the Mile."

The winner of seven consecutive Group 1 races, the last five at a mile, Rock of Gibraltar may go in this Saturday's Queen Elizabeth II Stakes at Ascot. He is one of six O'Brien trainees still eligible for the one-mile Group 1 race that usually serves as a key Breeders' Cup Mile prep, but was used by O'Brien to prepare Giant's Causeway for the Breeders' Cup Classic two years ago.

O'Brien faces the problem of choosing either Rock of Gibraltar or Hawk Wing as his Queen Elizabeth II runner. He has said that only one of them will go. "If the ground remains good or better as it was on Tuesday, Hawk Wing would run accompanied by Sholokhov as his pacesetter," he said. "If the ground softens up, Rock of Gibraltar goes with Sahara Desert as his pacesetter."

In fact, O'Brien said that not only is Rock of Gibraltar still a Classic possible, but so too is Hawk Wing, the recent nose runner-up in the Irish Champion Stakes, and High Chaparral, the Epsom and Irish Derby winner who is still being aimed at the Arc on Oct. 6. But High Chaparral is also a Breeders' Cup Turf possible, while Hawk Wing could wind up in the Mile if Rock of Gibraltar goes in the Classic.

"We won't make any final decisions until after Arc weekend," O'Brien said