Mayhew, 53, was promoted to interim general manager of after the Lions fired Matt Millen back in 2008. He was eventually hired on a full-time basis and spent eight years with Detroit.
The Lions elected to fire Mayhew after the 2015 season and hired Bob Quinn as his replacement.
Mayhew took a position with the Giants as their director of football operations/special projects for the 2016 season and joined the 49ers in 2017 as a senior personnel executive. He was promoted to vice president of player personnel in January.
During his time in charge of the Lions, Detriot produced a record of 41-63 (39.4 percent).