NEW YORK -- Another piece in a puzzle that the Mets hope one day will lead to years of long lasting success arrived at Shea Stadium in unexpected fashion Monday evening.

Mets manager Willie Randolph wouldn't rule out the possibility that 21-year-old outfielder Lastings Milledge would remain with the team after Xavier Nady recovers from an the emergency appendectomy he underwent at 4:30 a.m. on Tuesday.

But Randolph and Mets general manager Omar Minaya tempered their excitement at the arrival of Milledge, the team's first choice in the 2003 First Year Player Draft.

"Anything is possible," Randolph said. "Right now he's just up here to help us until Nady gets back."

Milledge, who turned 21 on April 5, joins a team mixed with established veterans and those in a youth movement that includes third baseman David Wright, the team's top draft pick in 2001, and Jose Reyes, the 22-year-old from the Dominican Republic who was signed as a free agent in 1999.

Milledge went 1-for-4 with a double in his big-league debut in Tuesday's loss to the Diamondbacks. He played a clean right field as well.

"We decided to run the kid up here and give him the opportunity to play," Minaya said. "As I've said before, I'm always for giving kids an opportunity to play. And I think he's one of those kids who can come up here and help the team win.

"But at the same time, he doesn't have the pressure to have to help the team win. Especially as the club is today, because he doesn't have to be a savior. I think we have veterans around him who help him learn. Wright, Reyes and Lastings Milledge are our future and will play the kind of baseball Willie likes to play."

Milledge had a close call just to make his Major League debut. He'd been with the Triple-A Norfolk club playing a series in Pawtucket, R.I. The flight he was supposed to take from Providence to New York was cancelled.

"I thought I had a chance to come up this year, but maybe in September, or later in the season," Milledge said. "I was worried when I had to switch planes that I would never get out of Providence and that I would miss the biggest day of my life."

But there he was, just before the game, wearing No. 44 and running in the outfield just in time to bat No. 8 in the Mets' order that would face the Arizona Diamondbacks.

"I called my father,'' Milledge said. "I have this running joke with my father that I would call him when I got called up. I don't think he believed me."

Lastings' father, Tony, his mother, Linda, and brother, Tony Jr., plan to fly here from the family home in Tampa on Wednesday morning and see the new arrival play the final game of the Arizona series.

Randolph had a precise reason why he wanted Milledge, who was batting .291 (53-for-182) with 32 runs scored, 16 doubles, a pair of triples, four homers, 19 RBIs and eight steals with the Tides.

"We feel at this time he fits in with what we are trying to do right now," the manager explained. "He's the guy we feel can help us win games right now. We don't need a pitcher right now. We don't need a second baseman right now. When you lose a bat you want to replace it with a bat. That's pretty much why we made the decision."

The Mets said Nady had been feeling a bit under the weather for a couple of days. The right fielder was hit by a pitch on the left side of his back on Monday night and after the game told doctors he also had discomfort in his lower right abdominal area. He was checked out and it was decided Nady needed surgery immediately.

Nady was batting .267 with nine homers and 22 RBIs in 45 games, and had been a nice addition to the Mets lineup in the early going of this season.

"The conversation that I'm going to have with Lastings is when Nady gets back, Nady is going to be in the lineup," Randolph said. "Nady has performed pretty well, but I think the situation in this one is that it's an opportunity for a kid to get a taste of the Major Leagues without the feeling he has to be the guy."

Milledge left an impression on Randolph during Spring Training when the youngster batted .327 and behaved in a mature manner.

"The thing I like about him is he has a certain demeanor about him," Randolph explained. "He doesn't seem intimidated by too much. I look for that in young players. I look for fright, if they are intimidated or not. So far, from what I've seen, he's not intimidated by too much and that's always important in young players."

When teammate Cliff Floyd was asked the first bit of advice he got when he first arrived in the big leagues, he thought for a moment and said:

"Be on time."