Going from his Hall of Fame induction ceremony last Sunday to getting his number retired by the Mets on Saturday night in the span of a week made Mike Piazza, in his own words, “a wreck emotionally.”

But the player who is possibly the greatest-hitting catcher in baseball history did his best to keep his composure as he addressed an appreciative crowd at rainy Citi Field.

“With all due respect to Tom Hanks,” Piazza told fans before the Mets hosted the Rockies, “there is crying in baseball.”

Piazza’s No. 31 took its place in a new place for the few retired Mets jerseys — atop the stadium in the leftfield corner.

Until recently, the other retired numbers — Tom Seaver’s 41, Gil Hodges’ 14, Casey Stengel’s 37 and Jackie Robinson’s 42 — shared space with advertising signs behind the leftfield wall.

The team decided to make the retired numbers more visible just in time for only the second person along with Seaver to get the honor for what he did as a Mets player.

“I think it just shows the exclusivity of the club,” Piazza said. “Tom, obviously, the Franchise, and Casey and with the history, I think it’s a tremendous honor. I think every team has maybe a little bit different philosophy on retiring numbers, so I think it’s great that the Mets keep it very exclusive. So that’s even that much more special. It’s a wonderful club and it’s special to me.”

Piazza was flanked by his family and former teammates Al Leiter, Edgardo Alfonzo and Cliff Floyd as he spoke to fans from behind the tarp that was covering the infield.

In a nice touch by the Mets (and with nice meteorological foresight), a giant drawing of the Piazza patch the Mets wore on their uniforms Saturday night was painted on the tarp in front of home plate.

Piazza played for the Mets from 1998-2005. In 972 regular-season games with the team, he hit .296 with 220 of his 427 home runs. He came up as a Dodger, and also had brief stints with the Marlins, A’s and Padres. But his heart is in New York, as he proved when he went into the Hall with a Mets cap on his plaque.

Piazza talked about the enormity of making his Hall of Fame induction speech in front of so many of baseball’s greatest players on a very hot day in Cooperstown.

“I don’t know what giving birth is like,” he said, “but I sure felt like it after the speech.”

Saturday night was more like a special family gathering. The Mets family. Many of the fans wore some version of Piazza’s jersey. Piazza did not; he wore a blue suit with no tie as he emerged from the first-base dugout.

“I think this occasion feels a little bit more festive, which is great,” Piazza said. “And it should be for the fans.”

Piazza’s special relationship with the fans didn’t happen right away. He was booed as only New Yorkers can when he struggled after the Mets acquired him from the Marlins on May 22, 1998, for Preston Wilson, Ed Yarnall and Geoff Goetz.

But Piazza soon turned it around and became a fan favorite because of the fierceness of his hitting. He signed a seven-year, $91-million contract — at the time the richest deal in baseball history — after the 1998 season to stay at Shea and helped lead the Mets to the 2000 Subway Series, among other memorable moments.

The only down note Saturday night was when Piazza thanked owner Fred Wilpon and team COO Jeff Wilpon and many fans booed. “No, no,” Piazza said.

Piazza closed with: “God bless you guys, God bless your families, and let’s go, Mets.” That went over better.

He then threw the ceremonial first pitch (following a familiar-looking crouch) from the tarp covering home plate to Leiter, who was near the pitching mound.

Earlier, Piazza had detailed his plans now that the Hall of Fame and number retirement ceremonies are in the books.

“I still think maybe when I get home — I’m so emotionally drained — I’m probably going to end up sleeping for a week straight,” he said.