Paul Nicholls believes it is "highly likely" Sam Twiston-Davies will partner Tidal Bay in the Crabbie's Grand National at Aintree on April 5.
With Ruby Walsh sidelined, the Ditcheat handler could turn to Twiston-Davies, who was successful aboard the popular 13-year-old at Wetherby in November.
Nicholls said: "It is highly likely that Sam Twiston-Davies will be riding Tidal Bay because he has won on him already this season."
Twiston-Davies said: "I have been lucky enough to enjoy a good record over the Grand National fences.
"I am not sure yet who I will be riding in the Grand National this year.
"My father (Nigel Twiston-Davies) has first choice but I could be riding Tidal Bay. We will just have to wait and see."
Grand National ante-post favourite is Teaforthree, who jumped well in the Betfred Cheltenham Gold Cup on Friday and finished third in last year's Grand National.
Trainer Rebecca Curtis said: "He is in great form and has come out of the Cheltenham Gold Cup really well.
"I don't think he had too hard a race, being allowed to coast home up the hill.
"He has eaten everything up and being freshened up out in the field - we will be hopeful of a good run."
Seabass has been withdrawn from the National after suffering a serious injury at Down Royal on Monday.
Trained by Ted Walsh and ridden by his daughter, Katie, Seabass was third at Aintree in 2012 and went off the 11-2 favourite under last year only to finish 13th.
Tidal Bay remains the top weight of the 73 horses still engaged after 27 came out at the latest forfeit stage.
Those to have been taken out include several others owned by Graham Wylie such as last week's controversial Cheltenham Gold Cup runner-up On His Own and the somewhat disappointing Boston Bob.
Others to have been scratched include Kauto Stone, Cantlow, Carlingford Lough, Cape Tribulation, Mon Parrain and Pandorama.
Only 40 horses can start, with four reserves. Currently sitting right at the bottom of those guaranteed a run is the David Pipe-trained The Package, who ran in the 2010 renewal and was an eyecatching third at Cheltenham last week.
The four reserves are currently Raz De Maree, Rose Of The Moon, Shakalakaboomboom and Alvarado.