Nicky Henderson has elected not to run Altior in the Betfair Tingle Creek Chase at Sandown on Saturday due to ground conditions.
The son of High Chaparral beat the popular Un De Sceaux in the Grade One contest two years ago, before going on to successfully defend his crown in the Queen Mother Champion Chase at Cheltenham and win a third Celebration Chase at Sandown to cap another flawless campaign.
Last season was not so smooth, however, with Altior suffering a first defeat in 20 starts over jumps at the hands of Cyrname in an attritional affair at Ascot - which put paid to ambitions of a step up to three miles for the King George VI Chase.
Henderson's superstar chaser got back on the winning trail at Newbury in February - and while a late setback ruled out a Champion Chase hat-trick bid, the 10-year-old had since demonstrated to his trainer that he was back firing on all cylinders for his eagerly-awaited reappearance.
But after taking stock of the ground following racing at the Esher circuit on Friday, Henderson told the PA news agency: "It is with a heavy heart we have decided that Altior is not going to run. We simply don't want to bottom him again given what happened last year.
"Everyone has seen how testing the ground was today and we're not going to ask him to do it again.
"We're very sorry to everyone who was looking forward to seeing him and it was a very tough decision for the Pughs, but we've got to do the best thing by the horse.
"It's tough, and if there was any further rain forecast we may have left the decision until the morning, but it will be very holding ground and very hard work.
"We've been talking all night, we started off at 50-50 but we're not even 90-10 now - he won't run.
"Sadly, the horse could not be in better form so we'll look at either Kempton or Ascot for him next."
The race will still see Paul Nicholls fire a twin assault in a bid to add to his record haul of 10 Tingle Creek successes - with 2017 winner Politologue, who landed the Champion Chase when last seen, joined by recent Haldon Gold Cup hero Greaneteen.
Politologue carries the colours of John Hales, who said before news of Altior's absence: "I'm sure he'll give his best, as he always does.
"It's a good field. Politologue is in good condition, and I think you'll find that he's been well prepared for the race - there'll be no excuses if we don't win.
"He obviously won the race a few years ago, and bled in the race last year, but Paul devised a new way of training him after that - which paid off at the Festival."
Nicholls told Betfair: "Greaneteen won the Haldon Gold Cup in determined style at Exeter, staying on stoutly. Although he has earned a crack at this Grade One and has come on bundles since Exeter, he does need to improve - because Politologue is rated 10lb higher than him.
"Greaneteen is what I call a strong-staying two miler, which is what you want for a race like this, and it wouldn't surprise me to see him right in the mix.
"We know Politologue is best fresh - he looks stunning, has had an away day and couldn't be in better shape.
"The more it rains at Sandown, the more it will suit him."
Harry Whittington is still intending to step Rouge Vif up in class, after he impressed in handicap company at Cheltenham in October, but will check on ground conditions before confirming his participation.
He said: "I'm just hoping there's some good to soft in the going description - if there's more rain and it turns soft, then I think we'll probably be a non-runner.
"He's in great form, and his preparation has gone very well. He was ready to run in the Shloer Chase at Cheltenham last month, and we pulled him out of that because of the soft ground.
"If we do run, hopefully he'll run a big race. It's very tough, but he's earned his right to have a go - and hopefully he can show he can mix it with the big boys."
The field is completed by Olly Murphy's Brewin'upastorm and Pat Fahy's Irish challenger Castlegrace Paddy, who won the Fortria Chase at Navan last month.
Fahy said: "Everything has gone well since Navan. I couldn't be happier with the horse - I've never seen him as well in himself.
"He's an outsider, which is great - that's the way I always triumph. As long as the horse is well, that's all you need to worry about.
"It's going to be an enjoyable day for us. He's entitled to go, and we're looking forward to it."