The gesture came as the Yankees played their first home game following the 30th anniversary of Munson's tragic death in an Aug. 2, 1979, plane crash.
"I just wanted to give a little tribute," Posada said. "Thurman is special to me. It's one night; hopefully I don't get fined for that. I just wanted to let everyone know I was thinking about it."
Posada used the same numeric decals that adorn his batting and catching helmets, with No. 20 displayed on the brim. He placed Munson's retired digits on the mask padding near his right cheek, opposite a Nike swoosh.
In Posada's locker at Yankee Stadium, there is a framed yellowed photograph of Munson, accompanied by the following quotation:
"Look, I like hitting fourth and I like a good batting average. But what I do every day behind the plate is a lot more important, because it touches so many more people and so many aspects of the game."
Posada found the clipping in a workout room at -- of all places -- Fenway Park and stashed it for his own collection. Though he never saw Munson play in person, Posada has since felt a sort of kinship with the fallen backstop.
He said that he has spoken with many of Munson's former teammates -- Ron Guidry, Goose Gossage and the late Bobby Murcer among them -- during Yankees Spring Training camps about what kind of man he was.
"Great teammate," Posada said. "That's all they talked about, a great teammate and a guy that really wanted to be out there every day. Nobody loved playing the game more than him. It was good to hear those things."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.