Trainer Nicky Henderson says Altior remains in the running to defend his crown in the Queen Mother Champion Chase at Cheltenham despite an injury scare.

Henderson announced on Sunday the brilliant two-miler was lame after a dormant splint that had caused no problem to the 10-year-old previously "reared its ugly head".

Work on a water treadmill has helped, and the trainer was more upbeat on Monday (Tuesday AEDT) .

"We have declared this morning. He has improved considerably. He would not be able to run today, but we have got 48 hours," Henderson told the Press Association.

"If it continues to improve as much as it has done since last night to this morning, he's got every chance.

"We have to give him every chance, it's only right. I've been in touch with the British Horseracing Authority vets as well.

"If it was today, no you wouldn't run, but the improvement has been significant enough to justify leaving him in and seeing how we are going tomorrow. If necessary we'll have to take it to the wire."

Beaten for the first time over jumps at Ascot in November, the Patricia Pugh-owned gelding returned to his best in the Game Spirit Chase at Newbury last month.

Should he line up on Wednesday, Altior will be bidding for his fifth win at the Festival, having taken the Supreme Novices' Hurdle and Arkle Trophy before his two Champion Chase victories.

Defi Du Seuil has been the new kid on the block this season and he heads Altior's opposition.

The Willie Mullins-trained Chacun Pour Soi is the sole Irish contender, but is highly regarded and he did beat Defi Du Seuil by 4-1/4 lengths in the Ryanair Novice Chase at Punchestown last May.