Having saddled Sharp Rise to finish third in the race for owner Robert Aplin last year, the Chipping Norton handler hopes the nine-year-old can better that effort on October 21.
The former Nicky Henderson-trained gelding will enter the two-mile-five-furlong contest on the back of a victory after gaining his first success since switching to Longsdon at Perth last time out.
Longsdon said: "He will go straight to America for the National there. He has already been a fun horse.
"The decision has been made that he will fly out to America around October 10/11 and the race is on the 21st.
"That will be fun. We will try to finish off what Sharp Rise couldn't quite do last season for the owner.
"Nothing against Sharp Rise, as he was an amazing horse, (but) this horse is a better horse. Even when he comes back to the UK, I would like to think he could hold a high rank here
"He was a very lucky buy for the owners."