Sprinter Sacre features among 26 entries for the BetVictor Queen Mother Champion Chase at the Cheltenham Festival on March 12.
Nicky Henderson's superstar has questions to answer after being diagnosed with a fibrillating heart on his first start of the season when pulled up at Kempton.
While his participation is still in the balance, last year's winner remains the standout contender.
Henderson has also entered Captain Conan, Kid Cassidy and French Opera.
Paul Nicholls has given King George third Al Ferof the option and has also entered his top-class novices Dodging Bullets and Hinterland.
Sire De Grugy took advantage of Sprinter Sacre's ailments at Christmas and is a possible for Gary Moore, while former winner Sizing Europe could have another crack for Henry de Bromhead, who has also entered Special Tiara.
Last year's Arkle runner-up Baily Green, Tony Martin's Benefficient, Willie Mullins' pair of Arvika Ligeonniere and Twinlight and John Hanlon's Hidden Cyclone are all also engaged.
One notable omission is Colin Tizzard's Betfair Chase winner Cue Card, but he has been entered in the Ryanair Chase.
De Bromhead has also entered the veteran Sizing Europe in the Ryanair and he will now head straight to the Festival after disappointing at Leopardstown over Christmas.
"Hopefully, Sizing Europe will run in either the Queen Mother Champion Chase or the Ryanair Chase. They are provisional entries and we are not leaning either way at this stage," said De Bromhead.
"He has been fine since his run at Leopardstown. He was a little disappointing and didn't really attack his fences as he normally does, but there were various reasons, with the ground being the main one. He will go straight to Cheltenham now and hopefully he can bounce back."
Special Tiara beat Overturn in a Grade One at Aintree last spring and finished third behind Kid Cassidy and Sire De Grugy at Cheltenham last time out.
Tizzard's stable star Cue Card enjoyed a nine-length verdict over First Lieutenant in the Ryanair Chase at the 2013 Festival and Mouse Morris' charge is also entered again.
However, both horses also hold engagements in the Betfred Cheltenham Gold Cup.
Cue Card has tackled longer distances in his last two starts, winning the Betfair Chase at Haydock and then finishing second to Silviniaco Conti in the William Hill King George VI Chase at Kempton.
There is a 20-strong Irish entry, though several horses hold alternative engagements. They include six from the Willie Mullins stable – Arvika Ligeonniere, Boston Bob, Marito, Prince De Beauchene, Rupert Lamb and Twinlight.