Shishkin could make his eagerly-awaited seasonal debut in the Ladbrokes Desert Orchid Chase at Kempton over Christmas if he pleases trainer Nicky Henderson is a second crucial workout next week.
The high-class chaser pleased his Seven Barrows handler at exercise on Friday morning - but he wants to put the seven-year-old through his paces again before deciding to head for the two-mile contest on December 27.
Shiskhin, who is unbeaten in his last eight starts, was last seen following up his Arkle Trophy triumph at Cheltenham with another Grade One victory in the Maghull Novices' Chase at Aintree in April.
He was to have started his campaign this winter in the Tingle Creek Chase at Sandown earlier this month, but Henderson was not happy with the horse's condition. His concern was justified when Shishkin scoped badly on the eve of the race.
Speaking at Ascot on Friday, Henderson said: "Shishkin worked this morning with Epatante, and another very good novice - not Constitution Hill - and he was good.
"He is clean. The vets happened to be in the yard because of Buzz (suffering an injury), so we scoped him and he is clean after a real gallop.
"I want to do that gallop again. It will probably be done on Tuesday, because the race is on Monday (the following week) and then I will talk to Joe (Donnelly, owner) and Nico and I will decide on Tuesday whether he is ready for a race the following Monday.
"If he is not ready, Joe Donnelly is fantastic. He says 'Nicky, if you are not happy, leave it - we will come here for the Clarence House (next month)'. But he is in good shape."