Casamento is set to contest the French Derby instead of competing at Epsom.
Godolphin currently have three horses entered in the Investec Derby but racing manager Simon Crisford has confirmed Ocean War as their only intended runner.
He will be the mount of Frankie Dettori, who landed the race in 2007 aboard Authorized.
Casamento will be rerouted to the Prix du Jockey Club, while Genius Beast is being lined up for a crack at the King Edward VII Stakes at Royal Ascot.
Casamento landed the Racing Post Trophy last year but paid the penalty for trying to live with Frankel through the early stages of the 2000 Guineas and trailed home 10th.
Crisford said: "Casamento will be confirmed for the Derby at the five-day stage but the plan is to go to the Prix du Jockey Club and he'll only be left in the Derby as a precautionary measure.
"I think we're going to go with Ocean War. Genius Beast will be confirmed as a precautionary measure but with him we're looking at the King Edward VII.
"We're very excited about Ocean War. He's in tremendous condition and has progressed extremely well from his last two races and we really believe a mile and a half around Epsom will suit him ideally."
Asked whether Dettori would ride, he said: "Absolutely."
