Trainer Aidan O'Brien on Friday confirmed that Mars, favourite for the Investec Derby since his debut win at Dundalk in July, will not run again this year but will be trained for a Classic campaign next year.
O'Brien said: "We kept Mars on the go after his Dundalk win, waiting for the ground to come right for him. That didn't happen, so we've decided to leave him off for the rest of the season.
"He's fine and got a good education at Dundalk. He will be trained with a Classic campaign in mind, possibly starting with the 2,000 Guineas."
Mars, a son of Galileo, is 10-1 for the Derby and 16-1 for the Qipco 2,000 Guineas.