well, it appears as if MacLean is purposely making sure that Filatov has a lot less pressure on him than Butler. Butler has the 1-way deal and played a lot of games down the stretch last season. He should be slightly more in sync with the team.
Filatov doesn't have the top 6 pressure to perform. He just has to go out there and play hard, be responsible and just get used to the system. He'll probably see PP time or even the odd shift on a higher line depending on how the game unfolds. But really, I think that they are easing him into the line up rather than throw him into the deep end.