Noel Meade has not ruled Harchibald out of the Smurfit Champion Hurdle despite the gelding disappointing in a gallop at Navan yesterday.
The County Meath handler was left "stunned" after the ante-post favourite failed to sparkle in a piece of work with four stablemates after racing.
Meade gave Harchibald a thorough check-up when he returned to the yard but nothing has come to light as yet.
"He seems fine. He came back after the work and we scoped him and checked him over and everything seemed OK," said Meade today.
"We haven't taken any blood yet but we will do that tomorrow too."
The six-year-old had been due to work at Leopardstown today but with heavy ground at the track, Meade opted to reroute to his local course.
Harchibald worked over a mile and three-quarters under Peter Kavanagh and although the ground was testing, Meade does not want to blame the conditions.
"It's a mystery why he should work as badly as he did. We were very, very happy with him going into the work yesterday but we were stunned by the way he worked," he explained.
"He had his regular work rider up and he said the ground was bad but I wouldn't put that down as a factor. We know he probably is better on good ground but I wouldn't have thought it would make him work as bad as that."
Harchibald has drifted out to 9-2 with Ladbrokes for the Champion Hurdle at Cheltenham on Tuesday week but Meade has not discounted the race.
"We will just have to see how he progresses now. I don't think I will be doing any long pieces of work with him but we will see how he goes and I might give him a little breeze later in the week," he added.
"I wouldn't rule him out of Cheltenham yet though."
PA