Sinking like a stone through the Mets’ lineup, Mike Piazza batted seventh last night for the first time since his rookie year with the Dodgers, 1993.

“It’s part of our lineup, that’s all,” Willie Randolph said before Pedro Martinez took the hill against the Brewers last night.

Piazza batted seventh in the order 13 times as a rookie and hadn’t been that low since 1993. Always a good soldier, Piazza took the news like a pro yesterday and said he’ll do whatever Randolph asks of him.

“It’s all touch-and-go and I’m basically just looking at the lineup, and if I’m in there I’ll do the best I can,” Piazza said. “If not, I’ll be ready when I’m needed.”

Piazza was not in the lineup Tuesday night, but won the game in the 11th inning when he drew a bases-loaded walk. He was back behind the plate last night and was expected to play today, breaking a practice of not playing in a day game following a night game.

The more Piazza speaks now, it seems as if he’s looking back over his career. The more he talks, it seems Piazza is looking forward to life after the Mets, perhaps as a designated hitter in the American League. He is in the final year of his contract with the Mets.

“I’m just at such a different point, and a good point, as far as my personal situation,” Piazza said when asked about hitting seventh. “I’m not really worried about it. It’s like no matter what, whatever [Randolph] feels is best, that’s good enough for me. Whatever is needed, whether it’s pinch-hitting or coming off the bench, batting fifth, sixth, seventh, it doesn’t matter to me. I’m just far beyond that, as far as I don’t really feel any . . . you don’t have to worry about me. I’m just going to go out there and do whatever I’m asked to do.”

Piazza has been embraced this season by the fans and regularly receives a warm ovation, which feels like the fans showing their appreciation for what he’s done here.

“Hopefully finish the year strong as a team and personally, as well as I can do to help the team,” Piazza said. “That’s the bottom line. Whatever my career holds in the future, I think the positives are if I can go out and do my role no matter what it is; if it’s coming off the bench or DH’ing when we play the American League teams or hitting fifth, sixth, seventh or eighth. It doesn’t matter.

“I’m just going to go out and do the best I can and hopefully hit according to the situation and that’s it.”