McNamara has worked in the sports department for the past 18 years, leading Nine’s cricket coverage for the past 9 years.
The Australian revealed details of an email from Head of Sport Tom Malone to staff.
“Buzz tells me he’s really torn in making this decision, but that after a great and lengthy tenure at Nine, it’s time for him to do something else,” he wrote.
“He’s going to have an extended break before seeking out a new challenge. He goes with all of our good wishes, and support, and of course he’ll always be welcome back in the Nine and WWOS family.”