All three contracts are for one year.
Mancari, who turns 27 next week, returns to the Sabres after a one-year stint with the Vancouver Canucks in 2011-12. Mancari notched 30 goals and 28 assists for 58 points in 69 games with the Chicago Wolves last season, and also skated in six NHL contests with the Canucks.
Originally drafted by the Sabres in the seventh round of the 2004 NHL Entry Draft, Mancari spent six seasons in the organization from 2005-11. The two-time AHL All-Star has compiled six consecutive 20-goal seasons, including 32 and 30 in his last two years, and has 181 goals and 238 assists for 419 points in 487 career AHL games with Chicago, Portland and Rochester.
A native of London, Ont., Mancari has appeared in 42 career NHL games with Vancouver and Buffalo, totaling three goals and 10 assists.
Porter, 26, originally drafted by the Phoenix Coyotes in the fourth round of the 2004 NHL Entry Draft, has spent the previous three seasons with the Colorado Avalanche. Prior to his trade to the Avalanche in 2009-10, Porter played with Phoenix for two seasons, spending time with their AHL affiliate, the San Antonio Rampage, as well.
In 163 NHL games, Porter has notched 25 goals and 20 assists for 45 points. He has 29 goals and 47 assists for 76 points in 98 career AHL games with San Antonio and Lake Erie.
The Northville, Mich., native was the recipient of the 2007-08 Hobey Baker Award while playing at the University of Michigan.
Leggio, 27, a native of Williamsville, N.Y., set career highs in 54 games for Rochester last season, compiling a 28-24-2 record with a 2.63 goals-against average. Leggio led the AHL in saves (1,721) and was named the team’s most valuable player.
Leggio has compiled a record of 50-38-2 in 92 career AHL games with Rochester, Portland, Albany and Binghamton. He played four years of collegiate hockey at Clarkson University before turning pro in 2008.