Sprint may be next in line to join Apple's iPhone ranks.

It's highly probable that a Sprint iPhone will debut before the year's end, according to Shing Yin, an industry analyst at Citadel Securities.

Because Verizon is ending its unlimited data plans Thursday, and because Sprint features cheaper pricing for comparable plans on AT&T and Verizon, the carrier "could offer an attractive proposition for more price-conscious users (a demographic that we think is increasingly important to Apple following the rise of Android)," and "could be a relatively stronger seller than the Verizon iPhone," according to Yin.

Yin's report is careful to mention that he doesn't think the actual device will be priced less than an iPhone from a competing carrier – just that Sprint's service plans cost less.

Expanding to other carriers like Sprint and T-Mobile would help give Apple a leg up against increasing competition from Android, which by many reports show it outpacing Apple sales and taking up a large chunk of the smartphone market.

Now that Apple's exclusive partnership with AT&T is over, it makes sense for the company to target the remaining big carriers in the United States to increase the iPhone's presence.

"The main thing for Apple is increased distribution, which is more important now than when the iPhone was first released," Yin told Wired.com in a phone interview. Distribution is a big advantage for Android phones, which are available in a multitude of models across multiple carriers, he added.

Apple rumors have increasingly focused on the company potentially releasing a more affordable iPhone for the masses. A statement by Apple COO Tim Cook saying that the company is "not ceding any market" seems to be the catalyst for much of the speculation, including the idea that there may be two new iPhone models in September. Currently, an unlocked iPhone 4 without a data plan goes for a whopping $650.

Although Yin's analysis is primarily speculation based on industry trends, a May report from AllThingsD from another analyst, Peter Misek, agrees that Apple's next iPhone won't be limited to AT&T and Verizon.

"Industry checks indicate AAPL has or is about to announce new carrier deals in time for the holidays with T-Mobile and Sprint," Misek wrote. "Additionally, we believe another China carrier could launch the iPhone in the next 12 months." On Apple's last earnings call, management was asked about launching the CDMA iPhone at other carriers, and responded: "We are constantly looking and adding where it makes sense, and you can keep confidence that we'll continue to do that."

And although competitors Verizon and AT&T would likely be displeased by Apple sharing the iPhone wealth with other carriers, they would be "unlikely to attempt to block Sprint from getting the iPhone," according to Yin.

Yin also says he wouldn't rule out T-Mobile from selling the iPhone in the near future, as well. Since Sprint is the next largest carrier after Verizon and AT&T, it makes sense that Apple would open the iPhone to their customer base next. "I would expect a T-Mobile iPhone soon after, though," Yin says.