Coneygree will not race before Cheltenham Gold Cup
Coneygree will not run before the Cheltenham Gold Cup and faces a battle to be ready for the 17 March race.
Mark Bradstock's 2015 winner returned from over a year out with a leg injury at Haydock in November, and impressed as runner-up to Cue Card.
But the nine-year-old missed the King George VI Chase on Boxing Day following an unsatisfactory workout.
"He's good and we're hoping he'll be ready to run in the Gold Cup," Bradstock's wife Sara said.
"He's fine, but he's jarred himself a little bit. It's not a serious injury, but as we all know, while he is a miracle horse, he is fragile.
"You never really know with him, but I'm hopeful he'll make the Gold Cup. We'll walk him now for a month until he's super-well and then we'll see where we are.
"He'll be fine by the time the Gold Cup comes around, the question is whether we'll have him ready."
BBC horse racing correspondent Cornelius Lysaght
It's striking how often a horse wins the Gold Cup in great style and is rated jumping's new shining light who might win a few big races. But things don't always work out like that.
OK, that didn't apply in the golden era of Kauto Star and Denman, or when Best Mate completed a hat-trick, but plenty of others didn't progress as anticipated - Imperial Call, the 1996 winner, is a classic example - and with Coneygree being still a novice when he was successful, hopes were sky high.
Good luck to the Bradstocks, but it all goes to prove how hard it is to keep champions at the top.