Season No. 9 for 49ers coach Kyle Shanahan comes with his staff’s most significant overhaul.

New coordinators are in place: Robert Saleh returns to the defense after three-plus seasons as the New York Jets coach, Brant Boyer leaves his post with the Jets to oversee the 49ers’ troubled special teams, and Klay Kubiak gets promoted on offense, where plays still will be called by Shanahan.

In a surprise, Brian Griese has been replaced after three years as quarterbacks coach by Mick Lombardi, who returned to Shanahan’s staff a year ago as a senior offensive assistant.

Griese has been a staunch advocate and mentor of Brock Purdy since his 2022 arrival as the NFL Draft’s last pick.