McCann, 31, made 45 appearances including 31 starts the previous two seasons. He had a guaranteed salary of $588,000 last season, according to the MLS Players Association.
The native of Ireland was a versatile player under previous manager Gerardo Martino, making starts at centerback or left fullback. However, the team signed free agents Brek Shea and Florentin Pogba, two more left-footed players, during the offseason, creating more competition on the left side of the formation. In that group also are George Bello, a Homegrown Signing, and Jose Hernandez, who seems likely to spend the season with Atlanta United 2.