Eight years ago, Paul O’Neill was thanked by the Yankees for his contributions to their dynasty with a plaque in Monument Park.

On Sunday, the Yankees retired his No. 21 — the 23rd player or manager in the franchise to have that happen.

This ceremony was slightly different from others.

Because he is not vaccinated against COVID-19, O’Neill couldn’t interact with any current New York players in the dugout. And with the Yankees stuck in a 4-14 rut, there were noticeable boos for managing general partner Hal Steinbrenner and general manager Brian Cashman during the 33-minute ceremony.

New York’s first jersey retirement ceremony since 2017, when Derek Jeter’s No. 2 was honored, had the usual video tributes and messages, gifts and an acceptance speech.

During his roughly eight-minute speech, the 59-year-old O’Neill — an All-Star right fielder and now a popular team announcer — thanked the fans numerous times. He opened by saying: “You Yankee fans have obviously been practicing and it sounds great still today.”

A four-time World Series champion as a Yankee, O’Neill was nicknamed “The Warrior” by late owner George Steinbrenner. “The fans remember the teams that win and we won,” O’Neill said. “And we won a lot.”

O’Neill hit .303 with 185 homers and 858 RBIs for the Yankees from 1993 to 2001. He was a four-time All-Star with the team and won the 1994 AL batting title during a strike-shortened season.

He wore No. 21 for his entire big league career, starting as a rookie with the Reds in 1985.

“That’s why I’m celebrating this day, because this is the biggest dream that I’ve ever had in my life,” O’Neill said in his speech.

Former trainer Gene Monahan was there, along with teammates Tino Martinez, Bernie Williams, Jorge Posada, Andy Pettitte and Mariano Rivera.

Six minutes into the ceremony, O’Neill stood next to his wife and family to unveil his retire number in Monument Park. He was brought on to the field in a golf cart as highlights played on the videoboard — including his final home game in Game 5 of the 2001 World Series and his running catch to end Game 5 of the 1996 World Series.

Then there were brief video messages from Jeter, Joe Torre, David Cone and Don Mattingly, along with a message from Roberto Clemente Jr., the Hall of Famer’s son and a former Yankee Spanish-language announcer.

“Obviously, Paul is a central figure in one of the many great times in Yankee baseball and dynasties,” manager Aaron Boone said before the Yankees faced Toronto, adding, “It’s fun to know Paul in a friendly, even silly guy that sometimes is a contrast with who he was in between those lines.”

Steinbrenner gave O’Neill a framed plaque of his jersey; other gifts included a custom wine bottle with his No. 21, a framed jersey signed by current Yankees and a water cooler, a nod to his tendencies to slam water coolers in the dugout.

The signed framed jersey was the closest thing O’Neill had to any interaction with New York’s current roster because of his vaccination status; unvaccinated personnel are barred from interaction with any players on the bench or in the locker room.

O’Neill has called games on the YES Network from his Ohio home since the pandemic 2020 season. In an interview with NJ Advance Media published Saturday, O’Neill said of his vaccination status, “I’d rather not discuss that.”

Since O’Neill retired after the 2001 World Series, the only New York player to wear No. 21 was reliever LaTroy Hawkins at the opening of the 2008 season, but he switched back not too long after the season started.