MacInnis, 22, recorded six goals and eight assists for 14 points in 59 regular-season games for the AHL’s Tucson Roadrunners last season. He added two goals and an assist in nine Calder Cup Playoff contests.
A second-round pick by Arizona in the 2014 NHL Draft, MacInnis has skated in 129 AHL games with Tucson and Springfield, totaling 14 goals and 17 assists.
Graves, 23, appeared in 23 AHL games with the Cleveland Monsters last season, recording three goals and three assists for six points. He also had four assists in 24 games with Quad City (ECHL).
Graves has played 42 games in the AHL over his first two professional seasons, compiling four goals and four assists.