The emerging smart watch market may soon have a major new -- and possibly disruptive -- entry. According to a new report, Apple will be releasing a smart watch this fall in different models, with more than 10 sensors to track health and fitness.

The report, in Friday's Wall Street Journal, cited "people familiar with the matter." It said the sensors are intended, in part, to counter questions about what a smart watch can do that a smartphone does not.

Avi Greengart, an analyst with industry research firm Current Analysis, told us that, "when The Wall Street Journal prints rumors, generally speaking they're not pure speculation" because of the quality of the publication's sources.

'Dovetails' with Health App

He noted that an emphasis on health and fitness tracking in a possible smart watch "dovetails" with the Health app built into the new iOS 8 that provides a dashboard for health data Relevant Products/Services from a variety of sensors and other apps, not to mention the new HealthKit tool for developers. Of course, Apple could also release another kind of device to collect such data, or could even not release such a device, but those possibilities are not likely.

"I am expecting Apple to launch complementary hardware to their software," Greengart said, adding that he expects it will be "something that fits on your wrist."

Additionally, the report indicates that the Apple smart watch line, which many believe will be called iWatch, will be available in various screen sizes. The specifics of only one device size was mentioned in the story -- 2.5 inches diagonally for the watch face. Shipments of such watches, according to one unnamed component supplier, are expected to reach as high as 15 million units by the end of the summer. Chief Executive Tim Cook has already said his company will launch new kinds of products before the end of 2014.

The publication reported that the Apple smart watch could be unveiled as early as October, with manufacturing by Taiwan-based Quanta Computing, which also makes Macs.

More Manufacturing Details

At least one other generally reliable source is also pointing toward the release of an Apple smart watch. Reuters news service, for example, also said Friday that Quanta Computer will begin production of Apple's smart watch, adding that the watch is already in trial production, and it pointed to July as the start date. Quanta, it said, will be the primary manufacturer, although LG Display will make the screens in the initial production run and Singapore-based Heptagon will make the sensor that monitors a user's pulse.

Citing unnamed sources "familiar with the matter," the news service also said the launch date will be in October. It noted that the watch face will protrude slightly from the band, and that the touch-sensitive device will be able to be recharged wirelessly.

The new watch will apparently stay within Apple's ecosystem -- Reuters says it will only be able to interact with other devices running the company's iOS, which means iPhones and iPads but not, say, Android or Windows phones.