Although Single Empire is a 50-1 chance, Harrison believes he has every chance of reaching the frame on the only colt in the race with winning form over a mile and a half.
"He did well to win in Italy because he got hampered and was taken back by the interference involving Kieren Fallon," Harrison said. "If Entrepreneur stays he will win, but I have had a good look through the race and I could see Single Empire finishing second or third."
Michael Stoute, Entrepreneur's trainer, will be double-handed as Tanaasa has been confirmed as a definite starter. Richard Quinn, overlooked for the mount on the third favourite, Benny The Dip, will ride the 100-1 chance.
The racing career of First Island, last year's Sussex Stakes winner, is in doubt after the colt sustained a spiral fracture of the right cannon bone while working on the gallops yesterday.
The Dick Hern-trained Sarayir will miss tomorrow's Oaks because of fears that the ground may be too fast.