Apple iPhone 5 release date rumors form a humongous file, and there is a palpable rumor fatigue in the market.

Yet one particular rumor -- about the next model of Apple's flagship phone coming to Sprint Nextel Corp. -- was received seriously and the carrier's stock rose more than 10 percent.

Sprint shares, which had received heavy pummeling of late, rose after the Wall Street Journal reported that the carrier will begin selling the iPhone 5 in mid-October. The Journal said according to people familiar with the matter, the new iPhone will be similar to the iPhone 4, but thinner and lighter with an improved digital camera and a new more sophisticated operating system.

The report, which was taken seriously by the markets, also brightens up iPhone 5 release date scenarios. According to it, the device will see the light of the day in mid-October.

If iPhone 5 comes to Sprint, it will significantly boost the carrier's prospects. While Verizon and AT&T have banked on the high-end smartphone sector to boost sales Sprint has so far been left out of the race. This can change now, and investors are weighing in on the prospects.

According to Richard Doherty, director of the research firm Envisioneering Group, iPhone 5 would help Sprint retain many of its customers itching to upgrade, the Journal reported. Sprint needs it... There are a lot of families that will embrace the iPhone.

However, there are downsides to this scenario as well, from Sprint's perspective. The addition of iPhone 5 could also hurt Sprint as it would boost AT&T's chances of winning regulatory approval for its $39 billion acquisition of T-Mobile, the report says.

That said, iPhone 5 could well be the White Knight for Sprint. Sprint has been struggling to expand customer base fast enough, leading to considerable investor angst. This was mainly because iPhone skewed competition among wireless rivals and created unequal sets of haves and have nots.

The WSJ report has been cited by various newspapers like the Los Angeles Times, but there has been no official confirmation from Sprint about it. Nor has Apple said when it will release the next generation iPhone. It has neither said the next iteration of its flagship device will be called iPhone 5.