[3] In his third season in 2008–09 with the Coyotes' AHL affiliate, the San Antonio Rampage, Sullivan developed his offensive instincts and led the team amongst defenseman in scoring with 32 points in 65 games.
[5] Sullivan was later returned to San Antonio without making his debut to lead the defense in scoring for a second consecutive season with 49 points and earn a place in the 2010 AHL All-Star Game.
[9] With the impending lockout coming to affect, Sullivan was assigned directly to the Avalanche's AHL affiliate, the Lake Erie Monsters.
[11] In the 2013–14 season, Sullivan failed to solidify a position among the defenseman of Modo and after 10 games he was mutually released from his contract after opting to join the Straubing Tigers of the German DEL on October 13, 2013.
[12] Sullivan instantly regained his scoring touch with the Tigers, and despite failing to qualify for the post-season, contributed with 4 goals and 27 points in 40 games.
After a single season with the Iserlohn Roosters, Sullivan joined his third DEL club in three campaigns, in agreeing to a three-year deal with the Hamburg Freezers on June 17, 2015.