The Nightingale is a top priced 16-1 for the RSA after giving trainer Paul Nicholls his fifth successive victory in the Pendil Novices' Chase at Kempton.
The 4-6 favourite jumped well throughout and pulled clear to beat Othermix with any amount in hand.
After the race, Nicholls ruled out a crack at the Arkle and confirmed he was likely to be aimed at the RSA.
He said: "The RSA is a possibility. He's well capable of running in it. There's no doubt he wants a trip and he's bred to stay.
"He won't run in the Arkle. If he doesn't go to Cheltenham, he'll go to Aintree for the two-and-a-half miler"."
