But we are talking about the Mets. “When you’re down by a ton, I’m not getting into that rah-rah voice,” she said. “I’m getting into, it’s serious but we’re still in this. ‘No. 9, Brandon Nimmo.’”

The Mets know all about being down by a ton. This is the team that was obliterated by the Washington Nationals 25-4 on July 31, the worst loss in Mets history. The Mets also know about being up by a ton, as when they beat the Baltimore Orioles 16-5 on Wednesday and the Philadelphia Phillies 24-4 on Thursday, becoming the first National League team to score at least 15 times in back-to-back games since 1933, according to the Elias Sports Bureau.

Ms. Castro did not have to deal with any of the lopsidedness. The big loss and the big wins came in away games.

Still, she said, “I would have loved to announce Jose Reyes as a pitcher” in the Washington game. Mr. Reyes, an infielder who was an entertaining and energetic shortstop when he was younger, was sent in to pitch the eighth inning. The Nationals scored their last six runs on him, including two homers.

Ms. Castro had been an English teacher at Poly Prep Country Day School in Brooklyn and a television reporter before the Mets hired her. She had worked for ABC News, WPIX-TV and ESPN, among other outlets. (She is one of two public-address announcers the Mets hired in the spring. The other is Colin Cosell, the grandson of the bombastic sports broadcaster Howard Cosell, who is often credited with having declared “Ladies and gentlemen, the Bronx is burning” during Game 2 of the 1977 World Series at Yankee Stadium.)

But being a voice of the Mets is different from working as a television reporter. “I don’t have to have my hair and makeup done, which is great,” she said.

Her usual game-day outfit is “ripped jeans and a T-shirt, and my hair is in a ponytail,” she said. “It is highly plausible to show up in sweatpants, but you never know when the Wilpons will show up.” (The Wilpon family owns the Mets.)