Trained by John and Thady Gosden, Stradivarius has won the last four Goodwood Cups and was aiming to record the same number of triumphs in the Royal Ascot highlight last month, but had no answer to Subjectivist, who has since suffered a season and potentially career-ending leg injury.
However, the Johnston camp on Wednesday supplemented the Paul Dean-owned Sir Ron Priestley, last seen winning the Princess of Wales's Stakes at Newmarket's July meeting and a Glorious Goodwood winner two years ago, for the Group 1, which John Gosden will not give up easily.
The joint-trainer was disappointed with Stradivarius's fourth in the Gold Cup and said: "He's been in good order since Royal Ascot. The Gold Cup was a fascinating race and Subjectivist put in a superb performance. I'd love to have got in a race with the winner, but we never had the opportunity to get there and that's life.
"I think Frankie [Dettori], having ridden him so brilliantly in previous Gold Cups, seemed to have a brainstorm and sit 12 lengths off the pace!
"I'm sorry that Subjectivist is not able to run next week, it's heart-breaking for everyone involved."
Serpentine, last year's Derby hero, and his Irish Derby-winning stablemate Santiago could represent Aidan O'Brien, while Spanish Mission and Trueshan also remain in the Goodwood Cup mix.
Goodwood also hosts the Unibet Lennox Stakes on Tuesday and 23 horses are entered in the Group 2, including last year's winner Space Blues, not seen since his Al Quoz Sprint ninth at Meydan in March.
His trainer Charlie Appleby could also be represented in the Group 2 Unibet Vintage Stakes with New Science, who might clash with unbeaten Coventry Stakes winner Berkshire Shadow.