The Sabres also announced the assignment of forward Mikhail Grigorenko to Rochester on a conditioning assignment was rejected by the NHL. Grigorenko, 19, will remain on the Sabres roster.
All three players were present for practice on Wednesday. The Sabres play at the Philadelphia Flyers on Thursday.
Adam is tied for the AHL lead in goals with 13 in 15 games. He also has a team-leading 18 points for the Americans. Adam has 14 goals and 25 points in 75 games over parts of three seasons with the Sabres.
McNabb played in the NHL with the Sabres during the 2011-12 season, scoring one goal with eight points in 25 games.
Grigorenko has two goals and three points in 15 games for the Sabres this season. The 12th pick in the 2012 NHL Draft, he had one goal and five points in 25 games during the 2012-13 season.