The buyout will make Grabovski an unrestricted free agent as of Friday at noon ET.
The Leafs have already used their other non-compliance buyout on defenceman Mike Komisarek.
Grabovski, 29, had four years remaining on his $27.5-million contract, which he signed in March 2012.
Acquired in 2008 from Montreal, the Leafs had high hopes for Grabovski.
But he struggled this season, recording just nine goals and seven assists in 48 games.
"This was not an easy decision to make as Mikhail made numerous contributions to our hockey club," Leafs general manager Dave Nonis said in a statement. "This is a roster move that will give us salary cap flexibility moving forward."
The move will free up $5.5 million of cap space for the Leafs.
In 367 career games, Grabovski has 94 goals and 123 assists.