Sunnyhillboy, runner-up two years ago, will not run in the Crabbie's Grand National at Aintree on Saturday-week.
Trainer Jonjo O'Neill took the decision to miss the great race after the 11-year-old failed to sparkle in a piece of work on Friday morning.
"He's been a super horse for us but he just didn't sparkle in his work this morning," said O'Neill.
"He's been great and we hope he'll be back next season" - trainer Jonjo O'Neill
"I had a word with Frank (Berry, racing manager) and JP (McManus, owner) and we've called it a day (for this season).
"Going for a race like that you have to be spot on and he just hasn't done what we'd have wanted in his last few bits of work, he's just not sparkling.
"He's been great and we hope he'll be back next season.
"We've still got Lost Glory, Twirling Magnet and Burton Port in there so hopefully they all get there in one piece."
Sunnyhillboy had been a possible National ride for Tony McCoy, and his choice now appears to rest between Ted Walsh's Colbert Station and the Martin Brassil-trained Double Seven.