As Baltimore Orioles star Pete Alonso recorded his 300th career home run against the New York Mets, his former team, it led to a fan reaction at Citi Field that not too many expected. While many Mets fans might have mixed feelings about Alonso hitting his 300th home run against the team, the fans in attendance cheered, as this former player gives insight into the reaction.

Alonso's home run came in the ninth inning, as it resulted in Baltimore tying the game, leading to a 7-5 win in 11 innings, with the New York crowd cheering for the slugger. Speaking on “Foul Territory,” ex-player A.J. Pierzynski mentioned that besides Alonso, the Mets fans' behavior during the series against Baltimore was also aimed at the team's management.

“This was more directed at other things than just Pete [Alonso],” Pierzynski said on the show. “And if you're a player and you're mad about this, then I don't know who you're mad at. You're mad at your pitcher for giving up the home run?”

“Are you mad at the team for losing? Why are you mad at the fans? The fans cheer for who they're going to cheer for,” Pierzynski continued. “When you do good, they cheer for you. When you do bad, they boo you. That's just the life of a professional athlete and someone in the spotlight.”

"This was more directed at other things than just Pete Alonso."

You can't really be mad at Mets fans for how they've expressed themselves this week, says @AJPierzynski12. pic.twitter.com/7dprGiAEfE

— Foul Territory (@FoulTerritoryTV) September 16, 2026

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More on the Mets fans' reactions to Pete Alonso

There's no denying that when Alonso signed with the Orioles in the offseason, it was a blow to the Mets fans, as the team didn't pursue hard enough to re-sign the ball club's all-time home run leader.

“So, I understand where they're like, ‘Man, I've never really seen anything like this.' You can't be mad at the fans of it. The fans are showing their love and support of the Mets, but they're also showing their displeasure at certain people in the Mets organization who they wanted to bring Pete back,” Pierzynski said.

At any rate, the series between the two teams ends on Wednesday.