The 11-year-old missed the Tingle Creek Trophy earlier in the month after scoping dirty, but pleased trainer Jessica Harrington in a spin yesterday morning.
Big-race rider Barry Geraghty was on hand to partner the dual Queen Mother Champion Chase hero in his work and Harrington is now targeting the Grade One event next week.
"He went well this morning and I'm very happy with him," she said. "Barry came down and rode him in just a straight piece of work and he seemed pleased with him.
"At the moment, all being well, he is going to run on Tuesday. Everything is back on track with him."
Moscow Flyer has suffered shock defeats on his last two starts, but is still a 5-2 chance with Ladbrokes to retain his crown at the Cheltenham Festival in March.
Meanwhile, conditions at Sandown have dried out ahead of the Stan James King George VI Chase meeting on St Stephen's Day with the going on the chase course now officially 'good'.
Clerk of the course Andrew Cooper said yesterday. "It's been generally dry bar one wet night since the Tingle Creek, so that's not a problem. There is some talk of a bit of frost on Christmas Day though, so we are leaning towards a possible inspection, which will do no harm whatsoever."
Tony McCoy hopes to guide Impek to victory for Jim Lewis.
The champion jockey has been chosen over Timmy Murphy, who now rides Francois Doumen's L'Ami, to partner the Peterborough Chase winner.
While McCoy acknowledged Impek faces a huge test of his unquestionable ability at Sandown, the champion jockey insists Henrietta Knight's nine-year-old has nothing to fear taking on the likes of Kicking King and Kingscliff.
"The King George is going to be brilliant race with Kicking King, Kingscliff and Impek," said McCoy .
"It's going to be a very open race as horses like Royal Auclair have also got a chance, but it's something to look forward to.
"I've been very lucky (in Jim Lewis' colours) as I've won a King George (on Best Mate) and a Champion Chase (on Edredon Bleu).
"It would be nice for Jim Lewis if Impek can win and he's in good form but it's going to be hard to win."
Royal Auclair is likely to tackle the King George rather than take up an alternative engagement the following day.
Trainer Paul Nicholls has entered the eight-year-old for the Grade One highlight as well as the Coral Welsh National at Chepstow on Tuesday.
The Ditcheat trainer also has Hennessy third Cornish Rebel engaged in both races and with Royal Auclair set to shoulder top weight at Chepstow, Nicholls is leaning towards running at Sandown instead.
Meanwhile, Inglis Drever will face a maximum of 11 rivals in Tuesday's totesport Long Walk Hurdle at Chepstow.
Howard Johnson's Ladbrokes World Hurdle hero is sure to be a hot favourite following the news main rival Baracouda misses the race after meeting with a minor setback.
Trainer Francois Doumen was not totally satisfied with the 10-year-old after he worked yesterday and has decided to bypass the three-mile event.
Frank Berry, racing manager to owner JP McManus, explained: "Francois was not happy with him after he worked this morning, he just pulled up a bit stiff behind so he's going to have to miss the race."
Howard Johnson could have two strings to his bow as No Refuge is also entered, while Paul Nicholls has impressive novice winner Neptune Collonges in the three-mile contest.
Other notable possibles include Nicholls' Le Duc, the Alan King-trained pair of Crystal D'Ainay and My Way De Solzen, as well as Nigel Twiston-Davies' Mistanoora.