Last year's Randox Health Grand National third Vics Canvas will miss this season's race.
The 14-year-old developed a small problem after working at Fairyhouse this week but no final decision has been made on his future.
Connections wanted to take him to Aintree a fresh horse and he has not been seen since he defied his 100-1 starting price last April.
Trainer Dermot McLoughlin said: "He's not going to make Aintree, we've run out of time with him.
"It's just a small problem but it will prevent him from running this season.
"I haven't spoken to his owners yet about whether to keep going with him but the vet said there is no reason why not.
"It might be a bit much running a 15-year-old in the National, though, so we might look at the Foxhunters'."
Part-owner Gary O'Brien added: "He went well in a gallop at Fairyhouse on Wednesday but he wasn't right the following morning.
"I'd imagine we'll all have a board meeting before any decision about calling it a day or trying to bring him back again."