On the gallops with Kauto Star
Denman's chances of defending his Gold Cup crown have been dismissed by a preview night panel at Cheltenham.
The Paul Nicholls-trained horse cruised to a seven-length win over stablemate Kauto Star at the Festival a year ago.
But he lost in February on his seasonal reappearance at Kempton, after time out because of an irregular heart beat.
"He was a sick horse in the autumn," said Nicholls's rival trainer Alan King. "But the treatment he had has clearly floored him."
King added: "They got the heart back in sync, but the horse went through a real rough time.
"He might bounce back but I can't see him being back to his best this year."
Denman is third favourite for Friday's race in the ante-post market behind Kauto Star, who won in 2007, and another Nicholls-trained horse Neptune Collonges.
The preview evening, run by the Cheltenham and Three Counties Race Club, is the only one of its kind held at Prestbury Park ahead of the Festival.
The 2009 debate was chaired by Jim McGrath, the panel included King, journalist Matt Williams, jockey Paddy Brennan, punter David Nevison and bookmakers David Hood and Kate Miller.
The Festival opens on Tuesday, when the Champion Hurdle will be top of the bill, and runs for four days until Friday when it climaxes with Gold Cup day.