"He's the best goalie we've ever had," Dorion said. "It's time for us to take another direction and we thank him for everything he did."
The pending unrestricted free agent is the Senators' all-time leader in games played by a netminder. He's also tied with Robin Lehner atop the club's save percentage list with a .914 mark while having played 349 more contests with Ottawa than his fellow soon-to-be UFA.
Anderson, 39, spent nine-plus seasons of his 17 NHL campaigns with the Senators. Ottawa traded goaltender Brian Elliott to the Colorado Avalanche for him in 2011.
The Senators signed Anderson to a two-year, $9.5-million extension in September 2017.
He struggled while backstopping a rebuilding team in 2019-20, posting a .902 save percentage and minus-7.95 goals saved above average in 34 games.
Anderson won the Masterton Trophy in 2016-17 after taking several leaves of absence that season to spend time with his wife, Nicholle, who was diagnosed with throat cancer.