Grandouet doubtful for Saturday
Grandouet and connections
(Healy Racing Photos)
But Henderson stressed the issue "does not jeopardise his participation or prospects" as far as the Stan James Champion Hurdle is concerned.
In a statement issued to Press Association Sport, Henderson said: "First thing yesterday (Monday) morning Grandouet had filling in his near fore which had obviously been caused overnight.
"He swam, as he regularly does, and was seen by our vets and given some antibiotics to stop the inflammation. It has improved this morning but not by as much as we might have hoped.
"He will swim again today, have another two sessions in our spa and we will monitor the situation again in the morning. Depending on the progress, a decision will be made as to whether he can run in the Kingwell on Saturday.
"Should this not be possible, he will change the medication which will eliminate the filling instantly but prevent him from running this weekend, as this more aggressive medication is prohibited for racing purposes in the short term (one week).
"Whatever the outcome, this problem does not jeopardise his participation or prospects as far as the Champion Hurdle is concerned. There is no damage to any bone, tendon or ligament and he is 100% sound."
Tidal Bay has been allotted top weight of 11st 10lb in the John Smith's Grand National at Aintree on April 6.