Posada moved two steps in front of home plate, and Rivera flashed a wide grin while inching down to the manicured grass in front of the mound, zipping his toss to the catcher.
"It's the first time," Rivera said. "I hope it's the last time, too, at least when I'm playing."
Actually, as most will remember, there was a point when the Yankees thought Rivera's future might be as a starting pitcher. But the last time he held a baseball on the field for the first inning of a big league game was Sept. 5, 1995.
Celebrated on this evening in honor of his milestone achievement, coming in Sunday's 4-2 victory over the Mets, there was a neat twist from other ceremonies. Unlike when a Yankees great such as Yogi Berra is asked to take part in a ceremony, there was no question that Rivera would be able to reach the glove.
"I told him he should throw it left-handed," Yankees manager Joe Girardi said.
With video highlights of Rivera's first career save -- an eight-pitch outing on May 17, 1996, to preserve an 8-5 victory over the Angels for Andy Pettitte -- playing on the center-field video screen, Rivera's teammates dropped their gloves and applauded the future Hall of Famer. The Mariners also paid tribute from the top step of the visiting dugout.
"That's such a special moment for Mo," Alex Rodriguez said. "He's such an incredible pitcher and an even better person. It's a privilege and an honor to be his teammate."
The Yankees' elder statesman saved his best bullets for the real deal, pitching a 1-2-3 ninth inning to convert his 19th save in 20 opportunities.
Rivera, 39, is just the second pitcher in Major League history to reach the 500-save plateau, joining Trevor Hoffman (572) of the Brewers. He was named the American League's co-Player of the Week for the period ending Sunday, having earned a save in each of his three scoreless outings, allowing one hit with six strikeouts in three innings.