Leino was at the midway point of a six-year deal worth $27 million US.
He received the deal from the Sabres after a career season with the Philadelphia Flyers in 2010-11, when he scored 19 goals and 53 points.
The 30-year-old Finn would go on to score just 10 goals and 36 assists total in 137 games with Buffalo, missing nearly the entire 2012-13 season due to injury.
After Leino clears waivers, Sabres can buy out Leino's contract by paying him two-thirds of what he's owed over a span of six years. Buffalo could choose to use a compliance buyout, in which case the amount won't count against the club's salary cap.
Booth, 29, was due to make $4.75 million US next season, with a cap hit $500,000 less than that.
Booth scored over 20 goals on three separate occasions for the Panthers, but managed just 26 total in 134 regular season games with the Canucks.
The Dallas Stars, meanwhile, confirmed on Tuesday that a compliance buyout would be used for Aaron Rome after the defenceman was placed on waivers the previous day.
Rome, 30, earned one assist in 25 games with Dallas during the 2013-14 regular season.
Dallas will pay out just over $1.05 million US to the veteran, spread out over two seasons.