Jarnet partnered Treve to her first three victories last season, completing the hat-trick with a brilliant display in the French Oaks, following which she was snapped up by Sheikh Joaan Al Thani’s Al Shaqab Racing operation.
After being announced as Sheikh Joaan’s retained jockey, Dettori took over in the saddle when Treve landed last year’s Prix Vermeille, but after being forced out of the Arc through injury, Jarnet steered her to a memorable victory in October’s Longchamp showpiece.
The popular Italian has been back on board this year, with Treve suffering a narrow defeat at the hands of Cirrus Des Aigles on her return to action in the Prix Ganay before returning with pulled muscles after finishing third in the Prince of Wales’s Stakes at Royal Ascot.
Head-Maarek feels reuniting the previously successful partnership will have a positive effect this weekend and going forward.
Speaking from Keeneland in America, she told Press Association Sport: “Frankie is not going to ride her in the Vermeille as I have decided Thierry Jarnet will ride. Normally, that means Thierry will ride in the Arc.
“It was my decision, nobody else’s. I think it is the best decision for the filly and when I told Frankie he was very good about it and understood my point of view.”
Al Shaqab’s racing advisor Harry Herbert stressed the rest of Dettori’s retainer was unaffected by the Treve decision. Herbert said: “These are difficult decisions, but Criquette felt that Thierry Jarnet knows the filly so well on a day-to-day basis and, having won an Arc on her, that for these last two key bullets (Vermeille and Arc) to fire in her career every little percentage shot counts and she wants to give the horse every chance.
“It’s obviously very disappointing for Frankie, but he’s a phenomenal team player. He’s been amazing on this.
“Frankie will be riding Osaila in the Moyglare in Ireland the same day and also riding the others for the Sheikh. It’s as simple as that.”