Everyone (the Devils included) already agreed that he would play this season in KHL, it isn’t a change of plans.
Some NHL ties:
Vitali Yachmenev was an Assistant Coach on Salavat Yulaev Ufa in 2018-19 & 2019-20. Yachmenev played with Fitz for 4 years when he was the inaugural Captain of the Predators. So he was around for Muk’s rookie season.
And the team has a new head coach, after two years as an AC there, former NJ Devils legend Viktor Kozlov got a promotion.
So at worst Muk get tips on dangling and how to be lights out in shoot outs.