Mike Sullivan used to talk about Matt Cullen as an extension of the Penguins' coaching staff when Cullen was still in Pittsburgh as a player.
After Cullen retired as a player following the 2018-19 season, the Penguins added him to the coaching staff in a player development role. With assistant Todd Reirden undergoing knee surgery on Feb. 14 as a result of a fall on ice in his driveway, an opportunity presented itself for Cullen to step in and take on a more prominent role with the Penguins' coaching staff for the time being.