NEW YORK -- The call came late Thursday night for Kirk Nieuwenhuis, when Triple-A Buffalo manager Wally Backman summoned the center fielder into his office. Two days after that meeting, and less than a year after injuries began derailing his path to the Majors, Nieuwenhuis made his big league debut at Citi Field.

"It feels great," Nieuwenhuis said. "I try to keep it on an even keel as much as possible, but it's been a little bit of a roller coaster for sure."

Had Nieuwenhuis not torn the labrum in his left shoulder last summer at Buffalo, he might have entered Spring Training as the favorite to become the Mets' starting center fielder. But because that injury prevented Nieuwenhuis from playing a full season at the top level of the Minors, the Mets traded for Andres Torres as a sort of center-field stopgap. Nieuwenhuis was again ticketed for Buffalo.

Yet things change quickly in baseball; Torres strained his left calf on Opening Day against the Braves, forcing the Mets to assign him to the disabled list and call up Nieuwenhuis.

His stay may be temporary, but Nieuwenhuis will receive plenty of playing time while he is here. Manager Terry Collins said the rookie will mostly platoon in center field with Scott Hairston, who will start Sunday against Braves left-hander Mike Minor.

"There's going to be plenty of at-bats for both guys," Collins said.

With Nieuwenhuis in center field on Saturday, the Mets started seven homegrown players against the Braves. The only exceptions were left fielder Jason Bay and pitcher R.A. Dickey, both of whom came to Flushing on free-agent deals.

Though the 6-foot-3, 215-pound Nieuwenhuis is not a prototypical center fielder, many scouts consider him a player greater than the sum of his parts. Nieuwenhuis does not boast elite speed, defensive ability or offensive prowess, but he has demonstrated competence in all of those areas.

"He's gotten better each and every year," said Collins, who first coached Nieuwenhuis as the organization's Minor League field coordinator in 2010. "He plays so hard. That's one of the things -- the intangibles he brings to us are that great energy and the way he plays the game."

Niese, Mets make five-year deal official

NEW YORK -- Discussions of Jon Niese's contract extension began in early March, weeks before Mets owners Fred Wilpon and Saul Katz settled their court case, closed on 12 minority ownership sales and paid back $65 million of outstanding loans.

"We may have reached this contract agreement anyway," general manager Sandy Alderson said Saturday, after the Mets announced Niese's five-year deal at a pregame news conference at Citi Field. "But it is hard to ignore the fact that these other issues were resolved."

Whether driven by outside influences or not, Niese's deal became official Saturday at a small pregame gathering. Worth $25.5 million over five seasons, the deal includes team options for the 2017 and '18 seasons that could increase its total value to $46 million.

"It's just an honor to play for the Mets organization," Niese said. "The fans, they're excellent. The city of New York is excellent, and I just love our teammates. I think we all get along. I love being a part of them, I get along with them and I just love playing with them."

In signing the deal, Niese became the only Mets player under guaranteed contract beyond 2013, though Jason Bay and Johan Santana both hold options for the '14 season. Niese is under contract through at least '16, and potentially longer should the Mets exercise one or both of his options.

It is a bit of a risk for the Mets, considering Niese, 25, has never thrown more than 173 2/3 innings or produced an ERA less than 4.20 over parts of four big league seasons. But the Mets are smitten with the left-hander's career ground-ball rate and five-pitch repertoire, and they believe he should at least remain a solid middle-of-the-rotation starter throughout the balance of this decade.

Had the Mets not extended Niese, he would have been arbitration-eligible for the first time after this season, likely commanding somewhere in the neighborhood of $5 million. From that perspective, the total value of his new contract is not much more than the Mets would have paid had they proceeded year by year with Niese throughout arbitration. But the latter route would have prevented the Mets from buying out at least one, and as many as three, of his free agent seasons at potentially reasonable rates. Niese would have been eligible to leave the Mets for the first time after 2015.

"What we're looking to do is build a core of players that can be Mets and make the Mets competitive for a long period of time," Alderson said. "I think Jonathon fits into that mold for us."

Worth noting

• Middle-infield prospect Jordany Valdespin started in center field Saturday for Triple-A Buffalo in a continued effort to increase his versatility. The Mets experimented with Valdespin in center toward the end of Spring Training, but they had indicated that he would go back to the infield once the regular season began.

• The Mets are auctioning off the "Carter 8" jerseys that players wore during Opening Day batting practice at Mets.com/gameused. The Mets Foundation plans to donate net proceeds to the Gary Carter Foundation.