Subjectivist was a stunning winner at Royal Ascot 2021 (Pic: Focusonracing)
Johnston told Lydia Hislop that his outstanding stayer will miss the rest of this season after suffering a setback and that retirement was a possibility given the four-year-old's potential as a stallion.
“He’s got an injury and it’s certainly season-ending," Johnston said. “There was no secret that the horse had filling in his left foreleg in Dubai straight after the race (Dubai Gold Cup) and we got a hell of a fright from that. Visually, that was a career-ending injury.
“Within 24 hours he’d got a reasonably clean bill of health and within a month he’d got a complete clean bill of health, which was very unusual for that type of situation. Everything went perfectly well and there were no issues going into the Ascot Gold Cup or afterwards.
Johnston tells Lydia Hislop about Subjectivist's injury
“But on Monday he had filling in the opposite leg. Because the left foreleg had been so atypical and he’d come back from that, we hoped it would be the same with the other leg, but it didn’t."
He added: "It’s devastating as he’s the most exciting horse I've had for a long, long time.The only positive we can take from it is that at least he did get the opportunity to show us what he could do.
“Those of us that were there in Dubai thought that was a phenomenal performance and at least it was confirmed in what I like to think was one of the best Ascot Gold Cups in recent days.
“I don’t know (if he’ll run again). He’s obviously a potential stallion. We’ll all have to look at what’s the best future for him. It’s not impossible he will be back for the Ascot Gold Cup next year but I think it’s highly unlikely he will be back before then."
Subjectivist was a superb five-length winner at Ascot last month when Stradivarius, seeking a record-equalling fourth win in the race, was among those left trailing.
The rematch between the pair in this month's Al Shaqab Goodwood Cup had been keenly anticipated, with both trading about 7-4.