Catenacci was Buffalo's third-round pick in the 2011 draft. He agreed to a three-year deal after completing his final season with OHL Owen Sound, where he finished second on the team with 72 points in 67 games.
Knapp, listed at 6-foot-6 and 222 pounds, was Buffalo's sixth-round pick in the 2009 draft. He agreed to a two-year deal after completing his college career at Miami, Ohio. Knapp is coming off a career-best season after going 15-9 with a 1.69 goals-against average and five shutouts.
The contracts go into effect next year. Both players are set to join Buffalo's AHL affiliate in Rochester on amateur tryouts for the rest of this season.