Trainer Paul Nicholls said Kauto Star, whose participation in the Gold Cup was in jeopardy following a schooling fall a fortnight ago, had returned from the race unscathed.
He said: "He's absolutely fine.
"Ruby wasn't happy after he'd jumped a couple of fences and we said if he wasn't happy to pull him up, and he's done the right thing.
"There's obviously something tweaking him."
Following the race he tweeted:
KAUTO STAR FINE.
More top news
Wrestling legend Jimmy Snuka has been charged over the death of his girlfriend more than 30 years ago.
Rogue landlords are making life unbearable for tens of thousands of tenants in England, according to Shelter.
David Cameron has announced plans for 18 more free schools and vowed to continue to open hundreds more in the next five years.