Star chaser Simonsig is set for a spell on the sidelines after suffering a setback in his preparation for the new campaign.
Nicky Henderson's dashing grey was unbeaten in three starts during his debut season over fences and completed his hat-trick in the Arkle Trophy at the Cheltenham Festival in the spring.
The seven-year-old headed ante-post lists for the William Hill King George VI Chase at Kempton on St Stephen's Day, but is "highly unlikely" to line up at Kempton, or anywhere else over the Festive period, according to his trainer.
Henderson told Press Association Sport: "We are just going to have to put his preparation on hold for three weeks as a result of a splint on his near fore.
"He was lame earlier in the week. He is sound now, but he was sore a few days ago and we had it X-rayed to have a look at it.
"We've decided the best thing to do is give it three weeks and see where are after that.
"He'll go in the spa and hopefully he can do some swimming exercise. He was quite forward in his preparation as well.
"We'll advise on where we are in three or four weeks. For the moment all plans are on hold, which is extremely frustrating, but it's one of those things.
"It's aggravating the horse and it's aggravating me and Ronnie (Bartlett, owner) as well, but that's horses and it always seems to happen to the good ones.
"Horses get splints all the time and only one out 100 actually interfere with what you're doing. Unfortunately, this is one of those.
"Three weeks takes us to the middle of November, so you'd have to say it's going to be difficult to do anything at Christmas. It's highly unlikely."