MetroPCS Communications Inc. (PCS) is slated to release early Tuesday preliminary customer growth data that could surprise many with its strength and put it on par with top-tier wireless carriers.

MetroPCS' net new wireless customer additions could prove to be a game-changer if the small pre-paid service provider shockingly surpasses several of the national players. Early data already point to the company having a strong quarter relative to its larger peers, according to industry observers. While MetroPCS releases the numbers on Tuesday, results from the other carriers won't be out until later this month.

It's a development that underscores a shift in customers actively looking to get away from the strings of a long-term contract and save money.

"The trend is that folks with landlines and cellphones are collapsing their plans into a single $40 to $50 unlimited plan," said Romeo Reyes, an analyst at Jefferies & Co. "If you're in a local area, this is a great product. You're saving $70 a month."

Wall Street analysts, on average, projected 554,000 net new customers for MetroPCS, although many believe the actual figure will be higher.

A spokesman for MetroPCS couldn't immediately be reached for comment.

Verizon Wireless - jointly owned by Verizon Communications Inc. (VZ) and Vodafone Group Plc (VOD) - and AT&T Inc. (T) have consistently been the leaders in the wireless industry, but the pre-paid players have slowly encroached upon their position. Leap Wireless Inc. (LEAP) and MetroPCS have already overtaken Sprint, and most eye Deutsche Telekom AG (DT) unit T-Mobile as the next to be passed.

"MetroPCS may be close to T-Mobile," said William Power, an analyst at Robert W. Baird & Co. "They've faltered a bit in the last couple of quarters."

Power added he would be surprised if AT&T and Verizon Wireless got passed. While the major carriers are seeing a more mature business, they still have the size, reach and existing distribution channels to keep their lead.

Spokesmen for T-Mobile USA and AT&T declined to comment. Verizon Wireless spokeswoman Brenda Raney said the competition has been around for a long time, and that the company has continued to successfully fend off its rivals.

MetroPCS and Leap are helped by their aggressive expansions into multiple new markets. Both companies offer calling plans in the $40 to $50 range that offer unlimited minutes and text messages, but restricted by geography. The companies are making a lot of noise in a key cites, as illustrated by MetroPCS' splashy launch in New York City and Boston.

Leap, meanwhile, is expected by analysts to post 420,000 net new customers helped by their launch in Chicago and Philadelphia.

"The footprint advantage AT&T and Verizon had a year ago is going away," Reyes said, calling the expansion a "game-changer" for Leap and Metro because their combined footprint quadruples with the expansions.

For example, AT&T added 2.1 million subscribers to bring its customer base to 77 million in the fourth quarter. But even AT&T is increasingly relying on pre-paid customers - 36% of last quarter's net additions didn't sign a long-term contract.

In comparison, MetroPCS finished last year with 5.8 million customers, and Leap had 3.8 million to close 2008.

The major carriers are eyeing the pre-paid market. Sprint Nextel Corp. (S) launched its Boost Unlimited $50 flat-rate plan early in the year, and the response has wildly surpassed expectations. Verizon Wireless has also tinkered with its pre-paid offering, although its presence in the area remains minimal.

In addition to Tuesday's customer numbers, MetroPCS reports earnings on May 7. Leap hasn't scheduled its quarterly report, but typically releases the results in May.

MetroPCS stock closed down 2.1% to $17.95 and is down to $17.82 in recent late trading. Shares of Leap ended the session down 1.2% to $35.08 and are down to $34.35 after-hours.

-By Roger Cheng, Dow Jones Newswires; 201-938-2020; roger.cheng@dowjones.com