Queen Mother Champion Chase hero Sprinter Sacre would have been a long odds-on favourite to take his unbeaten record over fences to 11, but misses out after returning a dirty tracheal wash earlier in the week.
But Henderson still has a major contender in Captain Conan, who has won three Grade Ones from three starts at the Esher track, and four in total as he rounded off last season with victory in top company at Aintree.
Henderson said: “Even if Sprinter was running this was a race for him (Captain Conan). I’ve no idea what he is going to end up doing, whether it is two miles, two and a half or three, but when he is fresh and well we should start him off over two.
“Even if Sprinter didn’t exist, this is a proper horse.”
Sire De Grugy leads the pack looking to profit from Sprinter Sacre’s misfortune.
The top-rated horse in the field by some margin, Gary Moore’s stable star was impressive on his seasonal reappearance at Chepstow in late October, and showed when winning the Celebration Chase in the spring the testing nature of Sandown holds no fears for him.
Sire De Grugy needs to bounce back from a shock defeat at Cheltenham last month, but Moore feels his seven-year-old is in a better place now – and a reason for the below-par effort has emerged.
He said: “I don’t think Cheltenham’s his track, a flatter track suits him. A different blacksmith shoed him, and the shoes that he put on were too wide. It was very frustrating, like he was skiing.
“It’s a different race now Sprinter Sacre is out, and I do think he’s the one to beat.
“Captain Conan has beaten us before, so we’ve got him to beat, but I’m really pleased with my horse.
“My only worry would be the back straight can dry out quickly at Sandown and we know Sire De Grugy is a better horse on softer ground – the softer the better.
“We know we’re not going to get his ideal conditions, so we’ve just got to make the best of it.
“At least he’s got course and distance form and I’m sure he’ll give a good account of himself.”
Henderson’s big rival Paul Nicholls fields the talented, but difficult-to-predict, Kauto Stone, who is fitted with blinkers for the first time.
The half-brother to the great Kauto Star chased home Sizing Europe in the 2011 Tingle Creek, but has failed to fire on his last four starts.
“He was disappointing at Down Royal last time and you just wouldn’t know what to expect from him. He’s very unpredictable,” said Nicholls.
“It’s obviously easier without Sprinter Sacre in the race and Kauto Stone was second a couple of years ago, so if he’s on a going day, who knows what will happen.”
Tataniano was formerly a very exciting two-miler for Nicholls, but was switched to trainer Richard Rowe earlier this year after losing his way.
Results have not improved much since and owner Andy Stewart is just hoping he can show some of his old spark.
Stewart said: “It’s a real shame Sprinter Sacre can’t run, but as he looked unbeatable before it gives the rest of us a chance.
“Tataniano was a very good novice – he won a Grade One – but he lost his way.
“It’s a £135,000 race and I like to support them. With no Sprinter Sacre there’s a lot of money going begging.”
The David Pipe-trained His Excellency is another horse chasing what is a sizeable pot.
Pipe said: “There’s a lot of prize-money on offer. We’ll see how much we can get.
“He will have improved for his latest run at Cheltenham. He’s got it to do, but you never know.”
The Mick Channon-trained Somersby is used to mixing it in this company and has a win in the Victor Chandler Chase to his name from 2012.
Last season he only ran three times, with limited success, but he returned to action with victory in the Haldon Gold Cup at Exeter, beating subsequent Betfair Chase winner Cue Card among others.
His regular jockey Dominic Elsworth said: “With no Sprinter Sacre it has really opened the race up.
“We were very pleased with him at Exeter, we beat Cue Card but you’ve got to be careful not to get too carried away about that as it was a handicap.
“He’s come out of that race well, he looks to have improved for the run also and the ground should be absolutely perfect for him.
“Last year was a complete washout but if you forget that he’s got a big chance, he pushed Master Minded to a short-head at his best.”