Unfortunately for the Leafs, he really was an internal rental piece for this year's playoffs as he will certainly be seeking more than the $1.645 million per season that he has earned the past two seasons.
Mikheyev had a career year this past season with 21 goals and 32 points in 53 games played. The penalty kill will be worse off next season without Mikheyev's speed. With the last couple seasons he's had he will be looking in the 3 million + range. That sort of price is highly unlikely to fit into the very tight jigsaw puzzle that is the Toronto Maple Leafs salary cap. With several important renewals yet to be signed, the team has just $6 million in cap space. But even if they had a ton of space, it's doubtful they want to overpay spark-plug winger whose ceiling is probably around what he accomplished this season.