Steve Jobs reportedly was present at Apple's campus on Monday, according to several witness accounts. An unnamed Reuters reporter claims to have spotted the executive at the company headquarters, where he chatted with another person while wearing his black turtleneck and bluejeans. If true, Jobs' presence at the Apple headquarters could indicate he is again taking hold of the reins following a six month leave of absence.

Other executives previously acknowledged that the iconic CEO has still maintained involvement with the company through his time off. Although Jobs has not yet announced a formal return to work, he was quoted in a recent press release regarding early iPhone 3GS sales. "Customers are voting, and the iPhone is winning," he observed.

Despite Apple's desire to keep details of Jobs' health a private matter, a source recently told the Wall Street Journal the executive received a liver transplant in Tennessee.

Although the transplant report remains unconfirmed, the Journal's apparent confidence in the claim and lack of sourcing has lead many, including John Gruber of Daring Fireball, to consider the possibility that the leak was intentionally placed by an Apple board member. The timing is suspiciously favorable for Apple, considering the iPhone 3GS launch earlier in the week. The story was also published late Friday night, a time when many people are not paying close attention to the news and the stock market is days from opening again.

The Journal story claims Apple directors were aware of the surgery. The board is known to receive regular medical updates by Jobs' doctor, although employees further down the chain would be unlikely to know specific details. Apple spokeswoman Katie Cotton claims the executive is on track to return in June, but there is "nothing further to say."