Nationals outfielder Adam Eaton was agitated Monday night. (Sarah Stier/AP)

NEW YORK — Adam Eaton and Todd Frazier have a history — an odd, unclear history — and it lengthened in the middle of the third inning at Citi Field on Monday night.

That part was evident, caught by television cameras, after Eaton grounded into a double play and the two exchanged words. After the game, a 5-3 loss for Eaton’s Washington Nationals to Frazier’s New York Mets, Eaton offered that Frazier started the dust-up by “chirping” at him from far away. Frazier, a veteran third baseman, declined to address the situation and called it “nothing.” The two were teammates with the Chicago White Sox for one season in 2016, and any beef goes back to those days.

They yelled across the infield during a game last August. Then their issues, whatever they are, sparked up again Monday during an otherwise dragging contest. Eaton, unlike Frazier, had a lot to say about the situation when asked about it after the game.

“Gosh, who knows what goes through that guy’s mind? He’s chirping all the way across the infield. He must really like me, ’cause he wants to get my attention,” Eaton said. "It seems like every time we come into town, he really cares what I think about him. I don’t know what his deal is, if he wants to talk to me in person or have a visit or what it is.

“But he’s always yelling across the infield at me, making a habit of it. He’s one of those guys who always says it loud enough that you hear it but can’t understand it.”

Eaton gave almost that exact same line — “says it loud enough that you hear it but can’t understand it” — after last season’s run-in. This time, the outfielder turned around, yelled “a few choice words” back, and they had to be separated. First base umpire Mike Estabrook stepped in front of Eaton. Frazier was restrained by a teammate just outside the Mets’ dugout.

But Eaton didn’t feel like Frazier really wanted to get close. It’s worth noting that, because Frazier declined to elaborate with Mets reporters, Eaton’s take and a few snippets of video are the only available accounts.

“It’s funny. I was walking toward him. He didn’t really want to walk towards me,” Eaton said. "But as soon as someone held him back, then he was, all of a sudden he was really impatient, like trying to get towards me. Just being Todd Frazier. What’s new?”

Not much. While Eaton and Frazier didn’t get along as teammates, and don’t exactly get along now, Eaton is surprised this has lingered into another year. But there will be many opportunities for it to be resolved in the future. The Nationals and Mets play three more games this week and, after that, have six additional meetings in the second half of season.

That’s plenty of time to make up and push this into the past. Or it’s plenty of time to chirp some more.

“He’s very childish. I’m walking with my head down, play’s over, I’m walking away. I can still hear him,” Eaton concluded, surrounded by reporters from Washington and New York at the end of the night. “I’m a 30-year-old man with two kids, got a mortgage and everything. He wants to loud talk as he’s running off the field. At the end of the day, I got to be a man about it. I tried to stay patient with the childishness, but it is what it is.

“I got to stand up eventually.”

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