Piazza's announcement drew quick reaction from the people touched by his career, such as Mets chairman and CEO Fred Wilpon, who saluted him "for his Hall of Fame caliber accomplishments in our game and with our team."
Chipper Jones of the Atlanta Braves -- Piazza's chief rivals both in his Dodgers days in the old National League West and later as a Met in the NL East -- called him "the best offensive catcher I've ever seen."
Piazza's afterthought selection by the Dodgers in the First Year Player Draft -- he was player No. 1,390 chosen, as a personal favor to Los Angeles manager Tom Lasorda, his godfather through a friendship with the family -- endured as the amazing backdrop to a 16-year career that produced 427 homers and a lifetime .308 average.
Of those home runs, 396 came as a catcher to shatter the previous record at the position, Carlton Fisk's 351. Next on that list are Johnny Bench (327) and Yogi Berra (306). All three are in the Hall of Fame.
"It has been an amazing journey," Piazza said in a lengthy statement released by his Beverly Hills, Calif.-based agent, Dan Lozano. "So today, I walk away with no regrets."
Lasorda called Piazza's career "one of the greatest success stories" that exceeded everyone's most reckless dreams.
"I can't say I knew he would turn out to be a Hall of Famer," said the former manager, a Hall of Famer himself. "But I saw the ability and nobody else saw it. Nobody wanted to draft him."
Piazza's final season, with the Oakland A's, turned into a strange farewell tour. He batted a typically solid .275 in 83 games as the Athletics' DH, but his return from an early May shoulder injury was delayed as Oakland considered putting him back behind the plate.
But after working toward that objective and a brief Minor League assignment, Piazza resumed his DH duties when he rejoined the A's in late July.
The A's were Piazza's fifth team, and the 2007 season was his only one in the American League. He spent his first 6 1/2 seasons with the Dodgers prior to a blockbuster deal to Florida, where he spent a week before the Marlins dealt him on to the Mets.
Following 7 1/2 seasons with the Mets, highlighted by his appearance in the 2000 World Series and two emotional confrontations with Yankees pitcher Roger Clemens, Piazza became a free agent for the first time and signed with San Diego.
He batted .283, with 22 home runs, in his only season with the Padres before moving north.
In his prepared statement, Piazza reflected on his New York years with particular fondness.
"Within the eight years I spent in New York, I was able to take a different look at the game of baseball," he said. "I wasn't just a young kid that was wet behind the ears anymore -- I was learning from other veteran guys like Johnny Franco, who taught me how to deal with the pressures of playing in New York, and Al Leiter, who knew what it took to win a world championship."
"Mike electrified New York City and energized our franchise after we acquired him in 1998," Wilpon said. "He was an integral part of our 2000 National League Championship club.
"Mike played the game with passion, class and heart -- symbolic of our city. We wish Mike, his wife, Alicia, and daughter Nicoletta all health and happiness as he begins a new chapter in his life."
Piazza also delivered a heartfelt message to the Shea Stadium fans who warmly adopted him:
"I have to say that my time with the Mets wouldn't have been the same without the greatest fans in the world. One of the hardest moments of my career was walking off the field at Shea Stadium and saying goodbye. My relationship with you made my time in New York the happiest of my career and for that, I will always be grateful."
"The guy could flat out rake to all fields," Jones said. "For a while, he was considered the best right-handed hitter in the game. You didn't want to see him come up with the game on the line, because usually he was going to hurt you."
Piazza never appeared frustrated by the absence of any tangible offers to remain on the field. Recently married and a new father, his announcement Tuesday came off as little more than a necessary formality.
"After discussing my options with my wife, family and agent, I felt it is time to start a new chapter in my life," he said in his statement.
His old chapter did not take long to unfold after his clandestine Draft selection.
Few people probably recall that Piazza was drafted as a first baseman, out of Miami-Dade College. Sensing his path to the Major Leagues would accelerate at a different, more demanding, less popular position, he took it upon himself to go to the Winter Leagues and learn to catch.
"Anyone who thinks anything was given to Mike because of Tommy has no understanding of what Mike had to go through," said Fred Claire, Dodgers general manager when Piazza was drafted and through 1998. "He earned every step, as well as my respect for all he accomplished."
His perception was perfect. Piazza made his Major League debut barely four years after being drafted, on Sept. 1, 1992 -- Mike Scioscia's final season as the Dodgers' longtime rock behind the plate.
Piazza batted .232 in 21 games in 1992 -- then quickly embarked on some of the most remarkable offensive seasons for anyone, much less someone who regularly squatted through 140 games.
In 1997, he batted .362, with 40 homers and 124 RBIs. In his first half-season with the Mets, in 1998, he batted .348, with 23 homers and 76 RBIs in 394 at-bats.
In his final three full seasons with the Dodgers, from 1995 through 1997, Piazza batted .348, with 108 homers and 322 RBIs. Discounting his debut September, his average did not dip below .300 until his 10th season, when he batted .280 for the Mets.
In that 1988 Draft, only five more players were even selected after Piazza. Out of that Draft's final five rounds, only two players ever made it to the Majors -- Don Wengert, a pitcher who would go 14-32 for six different teams, and Piazza.
An amazing journey, indeed.