Thistlecrack will miss the Timico Cheltenham Gold Cup and the rest of the season, assistant trainer Kim Tizzard told At The Races.
The 10-year-old looked a potential superstar when winning the 2016 King George VI Chase but a tendon injury sustained last February saw him miss the 2017 Gold Cup and kept him out of action until December.
A lacklustre return over hurdles was followed by a fourth-place finish on his return to Kempton in the King George, but Colin Tizzard's inmate is now set for another prolonged spell on the sidelines.
Kim Tizzard told At The Races: "He was a little bit stiff behind after the King George and he's been off and had X-rays and bone scans - it's gutting.
"He ran a screamer. He jumped really well and we were getting excited that the old Thistlecrack was still there.
"We were going for the Gold Cup - we're gutted. Hopefully he'll have his box rest and come back next season.
"We're gutted for the team, the owners, everyone. We've still got a horse, at the end of the day."
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