When the Mets induct Piazza into the club's Hall of Fame, they are most likely going to retire his No. 31 as well, which is something that every Mets fan would enjoy seeing.
Piazza is arguably one of the Mets' greatest hitters ever. Whether or not he is above Darryl Strawberry as a Met could be debatable, but there's no debate that Piazza is the Mets' greatest catcher and right-handed hitter, as well as the best overall player from the late 1990s through the middle 2000s.
He has the best slugging percentage in team history, is 10th in runs scored, eighth in hits, seventh in doubles, second in home runs, third in RBI, fifth in total bases and fourth in both batting average and on-base percentage (with a minimum of 1,000 at-bats).
All of those numbers, plus the numerous defining moments in his career that he had with the Mets are reasons why Piazza deserves to have his number retired. Only one player in Mets history has had his number retired. That was Hall of Fame pitcher Tom Seaver. Furthermore, Seaver threw both the last pitch in Shea Stadium history and the first in Citi Field history to Piazza, which shows that the team views them as the best hitter and pitcher, respectively, in franchise history.
Piazza changed the Mets from a good team in 1997 to a serious playoff contender a year later. The Mets ultimately fell short on the last day of the 1998 season, but won the NL Wild Card in 1999 and 2000, which culminated in a trip to the 2000 World Series against the Yankees. Piazza was the heart and soul of the team at the time and provided great leadership to a good group of teammates.
In 2001, the 9/11 attacks occurred, which was a huge blow to not just New York City, but the whole country as well. In the first game at Shea Stadium since the attacks, Piazza hit a go-ahead home run late in the game that not only gave the Mets a win, but it had a huge impact on both baseball fans and New York City residents that hope was on the way. It became the greatest moment in his career and only fitting that he was the one to lift everyone's spirits.
Piazza had two more great offensive seasons in 2001 and 2002, but the rest of his career with the Mets was not as good. The Mets played poorly from 2002 to 2004, and after Piazza missed most of the 2003 season with a groin injury, the team completely fell apart soon afterward. The fact that he was playing first base in 2004 ended up being a huge mistake by the Mets. Nonetheless, Piazza was able to mentor the Mets' younger stars at the time, such as Jose Reyes and David Wright.
The Mets over the years have been reluctant to retire the numbers of more players. Jerry Koosman, Keith Hernandez, the late Gary Carter, Dwight Gooden, Darryl Strawberry and Howard Johnson are just a few former Mets whose numbers could all have made a case for getting retired. However, Piazza defined a significant era in Mets history and no one has even thought about wearing his number ever since his contract expired after the 2005 season.
All in all, the Mets will do the right thing and retire Piazza's No. 31 on the day he gets inducted into the Mets' Hall of Fame. Hopefully, this will all occur next year.