In the absence of Ten Sovereigns and Advertise, the runaway Unibet Stewards' Cup winner was sent off one of three co-favourites, but having appeared to travel smoothly to the two-furlong pole, Khaadem quickly faded from contention to finish last of the 11 runners.
Hills said: "Before the race he had a bit of a bruised foot, but that came right and he was completely sound. I don't know whether the soft ground didn't suit him, but he's come back and he's sore in that foot again."
There are no immediate plans for Khaadem, who runs in the colours of Hamdan Al Maktoum and is a general 14-1 chance for the Qipco Champions Sprint at Ascot next month.
"He's still in the Champions Sprint which is something we might plan to do, but first we have to make sure he gets every bit of attention," said Hills.