"Kevin Pressman and I knew Peter from our time at Leicester," Shirtliff said.
"He was a consummate professional who loved the game, a great guy and a true friend. This is a very sad day for the Stags and for football in general."
Stags chairman Keith Haslam said "I am deeply saddened, and I would like on behalf of Mansfield Town to send my heartfelt condolences to Peter's family and friends."