New York Mets first baseman Lucas Duda (21) doubles to...

New York Mets first baseman Lucas Duda (21) doubles to right during the first inning of the game on Saturday, June 3, 2017 at Citi Field. Credit: Joseph D. Sullivan

It was back in 2000 when then-Mets bench coach John Stearns accidentally coined a rallying cry. After Mike Piazza collected a big hit, Stearns was caught on a mic screaming “The monster is out of its cage!”

Those were the golden days for the Mets, who haven’t had all that many happy days this year. And though no one is comparing anyone on the active roster to Piazza, there’s been a burgeoning sense that the collective offense — the monster that’s been caged, handcuffed and probably starved — is indeed stirring.

There is the promise of Yoenis Cespedes’ return, which Terry Collins said could come as early as next week, and Saturday night, there were the big bops off the bats of Neil Walker, Jay Bruce and Wilmer Flores. There was Lucas Duda collecting two more hits and proving that he’s in one of his Lucas Duda streaks — the ones that make you forget the swoons and just let you marvel at his raw ability.

“When he’s swinging good . . . he can carry it, and right now, he’s gotten big hits for us,” Collins said, also praising Duda’s eighth-inning web gem, when he made the first out with an over-the-shoulder catch. “Lucas Duda has always been a guy that can do damage. We’ve seen it as long as he’s been in the big leagues. Right now, he’s swinging very, very well. I hope he continues to swing well. He’s a big part of our lineup.”

And right now, his bat is tied to the Mets’ fortunes. With the Mets no longer able to rely on their starting rotation, offense is especially pivotal, which means that contributions from guys such as Duda and Bruce and Walker could very well shape what the Mets decide to do in the coming months. Either those three — all of whom will be unrestricted free agents after this season — help propel the Mets toward relevancy at the trade deadline, or they make themselves attractive trade chips.

Though nobody in the organization is discussing that now, the sense of urgency is unmistakable. “We’ve got to win a game,” Collins said after the Mets did just that, beating the Pirates, 4-2. “We’ve got to scratch our way back.”

On Saturday, they did it with the three home runs: Walker’s two-run blast plus solo shots by Bruce and Flores. Duda didn’t score or drive in any runs, but his contributions provided a morale boost. He had a double and a single, and in his last 12 games, he is 18-for-47 (.383) with six home runs, five doubles, 14 RBIs and nine runs.

He’s hitting .278 now — a 72-point improvement from May 21, when he was at .206 — with a .390 on-base percentage.

Flores came into the game hitting .375 since May 1, third among qualifying major-leaguers in that span.

“I think we’re all seeing the ball pretty well,” Duda said. “Jay tonight, Neil . . . It’s nice when things are clicking . . . Sometimes you’re hot, sometimes you’re cold. It’s the ebb and flow of baseball.”

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