NEW YORK - The Florida Marlins obviously didn't get the memo.

They weren't supposed to contend in the National League East this season. This tidbit might as well have been included on the news release when they traded slugger Miguel Cabrera and pitcher Dontrelle Willis to Detroit for prospects during the winter meetings.

The Marlins are rebuilding. Check back in a year or two. Thank you for your concern.

The Marlins' best days might still be ahead of them, but two months into the new season they sit atop the NL East as they come to Philadelphia to begin a three-game series with the second-place Phillies tonight.

"It's a test for us," said Phils manager Charlie Manuel, whose sizzling club has won four in a row by a combined score of 48-16 and trails the Marlins by a half-game. "They have talent, desire and fight. They have young players with a lot of energy."

In the off-season, few would have predicted this would be a first-place showdown. But the Marlins, who have baseball's lowest payroll at just under $22 million, refused to believe that they could not be a factor in the division that includes two clubs, the Mets and Phillies, with payrolls greater than $100 million. Florida got off to a good start and has maintained it - much as the Phillies have - with a strong offense and good bullpen work.

"Everyone except the guys in this clubhouse thought losing Cabrera and Willis was the end of the world," said Andy Fox, Florida's first-base coach. "But these guys are real grinders. They took it as a challenge. Now, there's a sense in here that we can do this."

"There's a real confidence building," said outfielder Luis Gonzalez, who has brought veteran stability to the team.

The Marlins swept the NL West-leading Arizona Diamondbacks last week, beating three pretty good pitchers in Micah Owings, Brandon Webb and Dan Haren.

"That series was like a wake-up call for us," reliever Justin Miller said. "It was like, 'Hey, we've got a legitimate chance.' "

The Marlins have reached the point in the season where outsiders are starting to wonder how long it can last, how long they can remain contenders.

Some teams take umbrage at these types of questions. Not the Marlins.

"I like what Dan Uggla says: 'Let everyone else try to figure it out. We'll just take care of today,' " Fox said.

Uggla, the hard-hitting second baseman, has been one of the key players in the Marlins' rise to the top of the division, and he is symbolic of the creative and diverse way the team was built, as well as the hungry attitude that the young players have. Uggla leads the NL in doubles (19) and shares the lead in extra-base hits (36) with Houston's Lance Berkman. He is tied for second with 16 homers and sixth with 38 RBIs.

Uggla was a Rule 5 pick from Arizona in December 2005. First baseman Mike Jacobs, shortstop Hanley Ramirez, starting pitchers Ricky Nolasco and Andrew Miller, and relievers Renyel Pinto, Matt Lindstrom and Kevin Gregg all came in trades. Rightfielder Jeremy Hermida and pitcher Scott Olsen came in the draft. Justin Miller was picked up on waivers after the Phillies let him go from their triple-A team in April 2007. Lefty Mark Hendrickson, who pitches against Brett Myers tonight, was signed as a free agent over the winter for $1.5 million. The former two-sporter, who spent time with the 76ers, has seven wins.

"What you have here is a group of young players turning the corner and becoming true big-leaguers," said Gonzalez, 40. "Your first couple of years in the majors, you're concerned about maintaining and staying. Now, these guys are at the stage where they are defending and winning."

The Marlins' most talented player is Ramirez, a big bat with speed who came to the team in the deal that sent pitcher Josh Beckett and third baseman Mike Lowell to Boston. Ramirez, 24, was the NL rookie of the year in 2006 and finished 10th in MVP voting last season.

"He's the most talented guy I've ever been around," said Fox, who spent nine seasons in the majors and called the likes of Derek Jeter and Bernie Williams teammates. "He still needs to do it for a few years to be in the category of those guys, but he's on his way."

The Marlins are coming off two losses to the Mets. Their bullpen gave up two leads in Wednesday night's 7-6 defeat in 12 innings. Still, the bullpen has figured prominently in the team's success. The Phils have the best bullpen ERA in the NL at 2.81. The Marlins are fourth at 3.15. The teams also rank one-two in the league with 79 and 76 homers.

"There's never a sense we're out of a game," Fox said. "We can swing it, and we have a good bullpen. This is a good club."

Good enough to stay around for the long haul?

"No doubt," former Phillie Wes Helms said. "This is a young, hungry team. These guys play hard every night. From what I've seen, it can definitely continue."

Contact staff writer Jim Salisbury at 215-854-4983 or jsalisbury@phillynews.com.