John Gosden believes the retirement of Kingman will rule him out of winning a second trainers' championship.
The three-year-old colt won seven of his eight races but was retired to stud this week after a sore throat ended his chances of running in the Queen Elizabeth II Stakes in October.
Gosden leads Richard Hannon in the trainers' championship by £145,500.
"I never thought I was favourite. I'm most certainly not now. I think I'm a drifting second favourite," he said.
It was hoped that Kingman would rekindle his rivalry with Hannon's Night of Thunder at Ascot next month, but the former's retirement means Newmarket trainer Gosden will not compete for the £567,100 first-place prize money.
Night of Thunder had beaten Kingman in the 2,000 Guineas in May, a month before the result was reversed in the St James's Palace Stakes.
Gosden was champion trainer in 2012, but with The Fugue, Taghrooda and Sultanina also set to retire, he expects to undergo a rebuilding process at his Clarehaven stables before challenging again.
"We've got four Group One runners retiring this year," he told BBC Radio Cambridgeshire.
"Group One winners don't grow on trees, you've got to find them again. So it will take another year to build up, but hopefully we have the horses coming through."