The Yankees said it was not clear whether he died Friday or Saturday. The team was not sure of the cause.

A moment of silence was observed before Saturday’s game against the Baltimore Orioles.

Newman was omnipresent for two decades at the Yankees’ minor league complex in Tampa, Florida, his portly frame easily recognizable from a distance. His tenure oversaw the rise through the system of Mariano Rivera, Derek Jeter, Andy Pettitte, Jorge Posada, Robinson Canó, David Robertson and Phil Hughes.

“You can’t reflect on the championships and postseason appearances during Mark’s time without recognizing how much he meant to the organization,” Yankees general manager Brian Cashman said in a statement.

“He had a great baseball acumen but also an uncanny ability to cultivate incredible loyalty and work ethic from the players he worked with, which was especially notable among our Latin players, whom he treated with a special care and respect. Countless players, even after achieving success in the majors, would always go back to him for advice.”

Newman was the Southern Illinois pitching coach from 1972-80, taking the job at age 22, and Old Dominion’s head coach from 1981-89. He joined the Yankees as coordinator of minor league instruction in 1989 and was promoted to director of player development and scouting in 1996, vice president of player development and scouting in 1997 and senior vice president of baseball operations in 2000.