General manager Doug Wilson said as much Monday, adding that the team will also replace top assistant coach Trent Yawney, who left to pursue a head-coaching job in the American Hockey League.
Nichol, Mayers and Wallin will become unrestricted free agents on July 1.
Nichol appeared in 135 games for the Sharks with eight goals, 18 assists and 26 points, while Mayer spent one season with the Sharks, scoring three goals and adding 11 assists. Wallin played in 97 games for San Jose with three goals and five assists.
Yawney spent three seasons on Sharks coach Todd McLellan's staff. He went 33-55-15 as coach of the Chicago Blackhawks during the 2005-06 season and the first 21 games of 2006-07 before he was fired.