The Ballydoyle trainer has won this Group One race for two-year-olds 11 times and appears to be leaving no stone unturned in his bid for a 12th success in the last 14 renewals.
Power has tip-top credentials with a hat-trick of wins, the latest coming in the Coventry Stakes at Royal Ascot.
O’Brien can also chose from After, Among Equals, Boris Grigoriev, Homecoming Queen and Reply.
Jim Bolger has Parish Hall and Somasach among the 14 five-day confirmations as he seeks to win this six-furlong heat for a fourth time.
Heading a strong British contingent is the David Brown-trained Frederick Engels, winner of the Windsor Castle and July Stakes.
Richard Hannon’s Lilbourne Lad, winner of the Group Two Railway Stakes over this course and distance, and Mick Channon’s Gatepost, fifth behind Power at Royal Ascot, are the other two UK entries.
La Collina, Qatar and Tough As Nails complete the list.
O’Brien has supplemented the three-year-old filly Empowering for the Patrick P O’Leary Memorial Phoenix Sprint Stakes over the same six furlongs on the same card.
He also has Zoffany in the Group Three dash for which there are 17 acceptors.
Zoffany took the Phoenix Stakes 12 months ago and has finished second in both the St James’s Palace Stakes behind Frankel and the Prix Jean Prat on his last two starts.
Newmarket trainer James Fanshawe has left in Deacon Blues but his Wokingham and Hackwood Stakes winner is also engaged in the Prix Maurice de Gheest at Deauville on Sunday.
David Barron’s July Cup third Hitchens, Ron Harris’s Secret Witness and the Mick Channon-trained Winker Watson are other possible British-trained challengers.
Tracey Collins has both Arctic and Oor Jock in the Phoenix Sprint Stakes, but has yet to firm up plans.
“If the rain comes, Arctic will probably run and if not Oor Jock probably will, but he also holds an entry on Thursday in Tipperary,” said the Curragh trainer.
“We’ll have a look at the two races and see what we are going to do.”
Meanwhile O’Brien’s Await The Dawn is the headline act among the 15 remaining entries in Sunday’s Keeneland Royal Whip Stakes at the Curragh.
The four-year-old’s sole defeat in six races came in the Champagne Stakes as a two-year-old behind Poet’s Voice.
He was last seen winning the Hardwicke Stakes at Royal Ascot by three lengths. Other entries from the Ballydoyle stable include Jan Vermeer, Viscount Nelson, Roderic O’Connor, Marksmanship and Gemstone.
The likes of Dunboyne Express, Casual Conquest and Jim Bolger’s incredibly tough filly Banimpire are others to catch the eye.
On the same card O’Brien’s Maybe could attempt to stretch her unbeaten run to four in the Keeneland Debutante Stakes.
Bolger has four entries in Criostal, Somasach, Teolane and Tiffilia.
Jeremy Noseda’s Illaunglass and Mark Prescott’s Kinetica could make the trip while Jessica Harrington’s Remember Alexander is another name to mention.
Elsewhere So You Think has been entered in the Cox Plate at Moonee Valley on 22 October.
O’Brien’s Coral-Eclipse hero has won the last two renewals of Australia’s weight-for-age championship when under the tutelage of Bart Cummings.
O’Brien has also entered recent Man o’War Stakes winner Cape Blanco — although the Ballydoyle duo are first likely to have to pass rigorous quarantine regulations.