Most Improved is still lame and will therefore miss the Qipco 2000 Guineas at Newmarket on Saturday week.
Brian Meehan's charge had been a leading fancy for the first Classic of the season over the Rowley Mile and was due to make his seasonal debut in the Craven Stakes over the course and distance last week.
However, last year's Dewhurst Stakes third was withdrawn from the Group Three contest on the morning of Thursday's race.
"Most Improved continues to undergo tests to diagnose the lameness reported on Thursday morning," the Manton trainer told www.brianmeehan.co.uk.
"The preliminary report from the vets has advised that he will not be ready for the Qipco 2000 Guineas on Saturday 5 May and he will be taken out of the race this morning.
"This is extremely disappointing for his owner and all of the team at the yard."
