Apple Inc. (NASDAQ:AAPL) is expected to unveil its widely rumored smartwatch, dubbed the iWatch, in September, according to a well-connected Apple blogger who provided the information in a post about the Moto 360 smartwatch planned by the Motorola Mobility LLC unit of Google Inc. (NASDAQ:GOOG).

According to John Gruber of Daring Fireball, the iPhone 6 will not be the only device that Apple is likely to introduce in September as the company will also unveil its first “wearable wrist thing” during the same month. Gruber’s claim challenges previous reports saying the iWatch could be launched later this year.

“It looks like Motorola’s designers tried to draw as much attention as they could to the 360’s stupid flat-tire display shape,” Gruber wrote in the blog post. “The only way this could get funnier would be if it doesn’t even ship until after Apple announces their wrist wearable thing next month.”

Gruber, who has a good track record in predicting Apple’s launch schedule, accurately forecasted last year’s launch of two iPhone models, the iPhone 5S and the iPhone 5C.

However, Gruber’s iWatch launch prediction contradicts a previous report by Re/code, which also has a decent track record of accurate Apple-related predictions. It said the iWatch could be unveiled at an event in October.

Based on a post on the Chinese microblogging platform Weibo, another report said last month that Apple could launch the 4.7-inch version of the iPhone 6 during its traditional September release time frame, but that the bigger 5.5-inch model could arrive in December, along with the iWatch.

KGI Securities analyst Ming-Chi Kuo also speculated this month that Apple may have delayed mass production of the iWatch to late November, according to the iDownloadBlog.

When it comes to features, the Wall Street Journal reported in June that the iWatch is expected to be equipped with more than 10 sensors, including ones that will allow the device to monitor users’ fitness. The Journal also reported the iWatch would be available in multiple screen sizes and that Apple could ship nearly 15 million units of the smartwatch by the end of this year.