MLB

Veteran looking like an Amazin’ Young-ster

Chris Young is partying like it’s 2009.

The last time the veteran righty felt this strong physically was the beginning of the season three years ago with the Padres. Various injuries and a major shoulder surgery later, he’s a glue to the Mets’ rotation.

Saturday he is scheduled to make his Subway Series debut when he faces the Yankees at Citi Field.

“He’s done what everybody has asked him to do — step in for Pelf as the starter and he’s done a great job,” catcher Josh Thole said yesterday, referring to the Mets’ loss of Mike Pelfrey to Tommy John surgery in April.

Young (1-1, 3.06 ERA) has been steady in his three starts since returning from 13 months on the sidelines after undergoing surgery to repair a torn anterior capsule in his right shoulder. His best performance might have come in a loss to the Reds last Sunday, when he allowed three runs, two earned, on nine hits and two walks over seven innings.

Young was asked if he’s surprised how smoothly it’s gone for him since returning.

“I didn’t know what the expectation should be, so if I expected to go back and pitch one start and go back on the DL, yeah, it’s been smooth,” Young said before the Mets’ 6-4 victory in the opener.

“But if I expected to come back and be Cy Young, it hasn’t been smooth. I didn’t know what to expect really, and it’s going well. It’s feeling better and better, my work in between starts and my arm feels it’s getting stronger and I’m able to do more and the results have been decent. I think there’s a lot of room for improvement.”

Young, who last faced the Yankees in 2005 with the Rangers, said it will be different doing it with the Mets. He got a sense of the fans’ enthusiasm for the Subway Series just by watching from the dugout at Yankee Stadium two weeks ago.

“It’s great energy in the park and you hear the ‘Let’s go Mets’ chants start up and then the Yankees fans would start booing,” Young said. “You don’t get that at normal games throughout the year. Certainly for our fans it would be important for us to fare well this series and for our own sake, too, to keep building momentum.”

mpuma@nypost.com