He had been an assistant coach under Ron Wilson, but was relieved of his duties after Wilson's firing. He has also been an assistant coach for the San Jose Sharks (under former San Jose and former Toronto head coach Ron Wilson). Zettler also served as colour commentator for
Washington Capitals radio broadcasts and provided commentaries on
San Jose Sharks radio broadcasts before becoming an assistant coach. While a member of the Sharks coaching staff, he provided insight into games during telecasts with updates before the start of the second and third periods. On March 2, 2012, Zettler was again relieved of his position of assistant coach to Ron Wilson in favour of another position within the Toronto Maple Leafs organization. In July 2012, Zettler was hired by the
Tampa Bay Lightning to be an assistant coach with their
AHL affiliate, the
Syracuse Crunch. After the promotion of
Jon Cooper on March 25, 2013, Zettler was named the head coach of the Crunch. Although Zettler coached the Crunch to their first ever Calder Cup Finals appearance in 2013, Zettler had minimal success as head coach of the Crunch. In three full seasons as head coach of the Crunch, Zettler led the Crunch to one playoff appearance in that time frame, in which they were swept by the
Wilkes-Barre/Scranton Penguins in round one of the
2015 Calder Cup playoffs. On May 10, 2016, the
Syracuse Crunch announced the hiring of
Benoit Groulx to replace Zettler as head coach of the team. On July 3, 2017, Zettler was hired as an assistant coach for the
San Jose Sharks, replacing
Bob Boughner, who was hired as head coach of the
Florida Panthers on June 12, 2017. When Boughner returned to the Sharks on May 29, 2019, he filled Zettler's position on the staff. On December 7, 2020, Zettler returned to the Lightning organization, becoming an assistant coach under head coach
Jon Cooper once again. ==Career statistics==