Outstanding jumper Bashboy will have four rivals in his bid to become the first three-time winner of the Grand National Steeplechase at Sandown on Sunday.

Bashboy is the $1.65 favourite with TAB fixed odds for the $250,000 race after a field of five was declared on Thursday.

The Ciaron Maher-trained Bashboy has convincingly won his past two starts in the Thackeray and Crisp Steeplechases but he has to contend with 74.5kg in Sunday's 4500m event.

He carried 68.5kg in his 2012 win and 72.5kg last year.

Last-start Grand National Hurdle winner Sea King, who has 69.5kg, is considered Bashboy's biggest danger with the Patrick Payne-trained gelding the only other horse under double figure odds at $2.60.

Sea King is one of two Patrick Payne-trained runners along with Australian Steeplechase winner Krase who is the outsider of the field at $26.