The Tom Scudamore-ridden 10-year-old blew the Newbury race apart on Saturday, and only stablemate Elegant Escape was able to stay with him in the home straight.
He will carry a 4lb penalty in the Chepstow marathon on December 27 if he attempts to achieve the double Tizzard pulled off two seasons ago with subsequent Gold Cup winner Native River.
“Both of them have come out the race very well. You would be brave not to go for the Welsh National with Sizing Tennessee,” said Tizzard.
“He’d won so well at Fontwell that if he was seven and not 10, everyone would have been raving about him. We will take a penalty for what he did on Saturday. It is the obvious race for him and he should be suited by it. If everything is fine he will be there on December 27.”