Dual Grade One winner Whisper will not run again this season, trainer Nicky Henderson has told bookmakers Unibet.

The Dai Walters-owned 10-year-old was under consideration for the Grand National, but his name did not appear when the entries for the big Aintree race were released on Wednesday.

Henderson said: “An issue reared its ugly head over the weekend and following veterinary investigations, and after discussions with his owner Dai Walters, it was decided that we cannot continue training him for the remainder of the season, so consequently he is out of Aintree and for the season. Horses are not machines and their welfare is of paramount importance to all of us.”

Whisper finished runner-up in the Ladbrokes Trophy at Newbury on his penultimate start, but was well beaten at Kempton on Boxing Day, when fifth to stablemate Might Bite in the King George VI Chase.