" Eddie Guardado changed J.J. Putz's splitter grip a few springs ago when they were teammates in Seattle, and Guardado says Putz really emerged after that.

According to Guardado, Putz's success was inevitable.

"J.J. was bound to happen," Guardado told The Post yesterday in a phone interview about the Mets' flamethrowing new set-up man. "He was a good kid and had a good head on his shoulders and he was willing to learn and take advice from the veteran players, and that's what he did."

The Mets acquired Putz on Wednesday night at the Winter Meetings in Las Vegas. The 6-foot-5, 250-pound power righty will set up Francisco Rodriguez at the back end of the Mets' now-impressive pen. Guardado, who spent two-plus seasons with Putz in Seattle, gushed about him yesterday, noting that Putz is a stand-up guy with the media and predicting he'd excel in New York.

New York isn't Seattle. But with Putz - who has racked up 91 saves the last three years - it might not matter.

"He's going to do tremendous. I really believe that," Guardado said. "Not only is he a good performer when he goes out there and toes the rubber every day, but he's a good person." "