Lyubushkin, 27, was set to become an unrestricted free agent in July.
The 6-foot-2 blue-liner has contributed one goal and one assist while averaging 15:30 of ice time over 31 outings this season. He also leads Coyotes defensemen with 77 hits.
Armstrong appears to be getting ahead of what projects to be a busy offseason for Arizona. Defensemen Alex Goligoski, Jason Demers, Niklas Hjalmarsson, and Jordan Oesterle are all impending unrestricted free agents.