Mancari re-joins the Sabres after spending last year in the Vancouver Canucks' organization. He had no points in six games with Vancouver and spent the rest of the season in the minors. Selected by Buffalo in the seventh round of the 2004 draft, Mancari had three goals and 10 assists in 36 games with the Sabres.
Porter has 25 goals and 20 assists in 163 career NHL games over five seasons split between Phoenix and Colorado. He played at Michigan and was college hockey's 2008 Hobey Baker award winner.
Leggio had a 28-24-2 record and led the AHL with 1,721 saves with Rochester, the Sabres farm team.