In November of 2008, Apple hired IBM’s Mark Papermaster to be Apple’s Senior Vice President of Devices Hardware Engineering, thereby replacing Tony Fadell as head of Apple’s iPod and iPhone divisions. A court deal later forced Papermaster to wait until April 2009 before starting at Apple.

Sixteen months later, Papermaster is out.

Per The Apple Core, speculation abounds that he’s the first casualty of the iPhone 4′s problematic antenna design, but neither Apple nor Papermaster have given a public reason for the departure, the current opinion having reasoned that he may have been asked to resign for the design flaw in Apple’s the iPhone 4.

Its suspect antenna design (dubbed “Antennagate”) has lead to rumors that its successor (the iPhone 5) is being to rushed to market and that it could come as soon as in January 2011, six months earlier than the traditional summer time frame for iPhone launches.

MacRumors chimed in with a rumor that Papermaster has been virtually invisible from Apple’s promotion of the iPhone 4, curious for the head of the department that designed it.

In retrospect, these current events should have cast a light during Apple’s iPhone 4 press conference last month. During the Q&A portion of the press conference, Papermaster, whose division designed the iPhone 4, didn’t seem to be in attendance at the event.

Even Apple’s promotional video for the iPhone 4 released at the device’s introduction in early June, which featured a number of Apple executives talking about the handset, failed to include Papermaster. Bob Mansfield is, however, featured with the job title of Senior Vice President of Hardware, dropping the “Mac” qualifier that had been part of his official job at that time. Per the New York Times, Mansfield was involved in the design of several aspects of the iPhone 4, including its A4 chip and Retina display.

Apple confirmed the shakeup at Apple’s most important devision in a statement to the New York Times stating that Papermaster is leaving the company. Apple noted that Bob Mansfield, senior vice president of Macintosh hardware engineering, who recruited Papermaster in the first place, will be assuming his responsibilities.

Stay tuned for additional details as they become available.