Might Bite is to undergo further veterinary examinations after flopping for the second time in a month.
The nine-year-old was last of seven finishers behind Clan Des Obeaux in the King George VI Chase on Wednesday.
A trickle of blood was found coming from his nose post-race at Kempton.
The disappointment by last season's King George and Aintree Bowl winner, and Cheltenham Gold Cup runner-up, followed a well-beaten effort at Haydock in November.
"The bleeding is obviously significant in the circumstances though it wasn't a terrible bleed, about two and a half out of five," trainer Nicky Henderson told BBC Sport.
"He'll canter on Monday and then be scoped and we can then send a sample off to see if he might have a bug or infection, which would be best as he can go onto antibiotics, if not then we're scratching our heads.
"It's worrying and disappointing, but it's our job to play it as we think is best."
After his 10th King George VI Chase win, Clan Des Obeaux trainer Paul Nicholls is looking at going for the Ascot Chase in February or going straight to the Cheltenham Gold Cup.
"Sometimes after they've run like that they take all day to eat their breakfast, but he ate up everything - he's very well and full of it, and we couldn't be happier," he said.
"Sir Alex [Ferguson, part-owner] was so delighted he was still texting me at about 11 o'clock last night."
The Nicholls team celebrated its second success at Grade One-race level in less than 24 hours when 7-4 shot Quel Destin tenaciously held odds-on favourite Adjali in the Coral Finale Juvenile Hurdle at Chepstow.