After side stepping an outing with the son of Galileo in the Sussex Stakes at Goodwood on account of the soft ground the Ballydoyle handler will now step the English and Irish 2000 Guineas winner up to a mile and a quarter.
Should Churchill take his chances on the Knavesmire it will see him renew his rivalries with Barney Roy, whom he finished fourth behind in the St James's Palace Stakes at Royal Ascot on his most recent start.
O'Brien told www.sportinglife.com: "Churchill looks like he is going to go there. We are happy with him and we are looking forward to it.
"If he is going to go there (mile and a quarter) we need to try it now. We always thought it would be well within his compass."
Churchill is a best-priced 7-2 for his first try at the distance, behind 100-30 Barney Roy and 4-1 Ulysees.
O'Brien added: "Capri is in it and Venice Beach is in it. That type of horse they are all there. The horse that won at Leopardstown the other night (Spanish Steps) is in it. So we have three or four possibles for that."Capri is the 4-1 joint-favourite with Crystal Ocean for the Doncaster Classic (PA)
Plans are in place to drop Washington DC back down to the minimum trip on the Knavesmire for a second shot at the Coolmore Nunthorpe Stakes.
The son of Zoffany gained his second win of the season after landing a six furlong Group Three at the Curragh on Sunday.
He added: "That is where he could end up next. A fast pace and following the other horses will suit him. That's very possible."