Nicky Henderson has reported that Shishkin “flipped his palate” in a piece of work this week and will need 10 days off while the problem is resolved.

While the procedure is not a major one, a new plan for the rest of the season will now need to be mapped out.

Having won his first 10 completed starts over obstacles, Shishkin has been beaten in his last two outings – pulling up in last season’s Champion Chase and finishing a distant third behind Edwardstone on his reappearance in the Tingle Creek at Sandown.

Following his most recent eclipse, Henderson stated his intention to step Shishkin up in distance and has not even entered his 2021 Arkle winner for the Champion Chase this time around.

He does, however, hold entries in the Ryanair Chase and, intriguingly, the Cheltenham Gold Cup, while the Silviniaco Conti Chase at Kempton next weekend has been mooted as a potential pre-Festival target.

Speaking in his Unibet blog on Friday, Henderson said: “After working earlier this week Nico (de Boinville) reported that Shishkin made a noise. We’ve never heard any noises from him before, not even a murmur, but Nico said there was a noise and we’ve investigated it and scoped him and he’d basically flipped his palate.

“It was clear and obvious. Essentially his palate is displacing, which is surprising as we’ve never heard it in a race but it’s highly like that it was indeed happening in a race. It’s a very easy fix but it’s 10 days off.

“We’ve got to do it, we’ll get on with it and get it done. It’s a common old problem and a very easy thing to fix, but it’s got to be done.”

The Seven Barrows handler did earlier provide an upbeat report on the well-being of star novice chaser Jonbon, however.

Runner-up to esteemed stablemate Constitution Hill in last season’s Supreme Novices’ Hurdle, the JP McManus-owned gelding is set to contest the Kingmaker at Warwick on February 11 on his way back to Cheltenham for the Arkle Trophy in March.

“Jonbon is very, very good. He’s had a nice little freshen up and he will start sort of doing his more serious work soon,” Henderson said at Ludlow on Friday.

“He is having a little hack around but he is very fresh and we’re having a job keeping his back down. He is very fresh and very well. He will go to the Kingmaker at Warwick.”

Henderson also confirmed his Relkeel heroine of last weekend Marie’s Rock will not run again before defending her crown in Cheltenham’s Mares’ Hurdle.

Stablemate First Street, third in the Relkeel, looks set for a drop in distance.

“Marie’s Rock has taken the race very well. I can’t see that she will run again, as I can’t see the race we can run in again,” the trainer said.

“I can’t see the point in running again. If she comes and does that first time out, it sort of tells you that you don’t need to – you’re as fresh as you can be.

“First Street ran a very nice race. I think you can conclude that he didn’t genuinely stay two miles and five furlongs in that ground. He is a two-miler at the end of the day.”