The 51-year-old jockey was criticised for his ride on Stradivarius in the Ascot Gold Cup and also in the Britannia Stakes where Saga was held by a head.
In fact, Dettori has only won one of his last 20 races and that was on the favourite Inspiral at Ascot.
Dettori will ride the Ralph Beckett-trained Lezoo at HQ but will not partner Sunray Major or Stowell who he has ridden regularly for the Gosdens.
Dettori's manager Peter Burrell told the PA news agency: "We're in the dark and searching for answers like everybody else."
Also speakng to Nick Luck's Daily Podcast Burrell said:
"He's riding in Istanbul on Sunday and he's got a ride at Newmarket on Saturday. I'm sure there'll be plenty of people out there who won't be watching him sitting in a weighing room and are only too happy to put him up on their horses," he said on Nick Luck's Daily Podcast.
"He's absolutely fired up. As we know we've had several peaks and several troughs and that's when he's at his most dangerous - he'll come out fighting. He's much tougher than people think."
John Gosden was key in rebuilding Dettori's career after his split with Godolphin and the pair have had huge success with the likes of Enable, Stradivarius, Golden Horn and Palace Pier.
Bookmakers Betfair have gone to the lengths of opening a market on who will become the next retained rider at Gosden's Clarehaven Stables, should the two part ways.
Hollie Doyle is considered a safe pair of hands and showed her talent with a win on Nashwa in the Prix de Diane for the Gosdens on Sunday and has been laid out as 4/11 favourite for the job.
James Doyle and leading Irish jockey Colin Keane are available at 7/1 meanwhile.
"Off the back of reports that Frankie Dettori won't be riding any of the Gosden runners in Newmarket, we have offered betting on who would replace him as stable jockey should the Calrehaven team wish to do so," said Betfair spokesman Barry Orr.
"With John Gosden having spoken so effusively about Hollie Doyle and her considerable talent on more than one occasion, she is a red-hot favourite to land the plum job that would see her and her husband, Tom Marquand, become the first power couple of Newmarket.
"Irish champion Colin Keane is also an interesting proposition, but it could take a lot to lure him away from Ger Lyons."