Tim Cook is a top candidate for GM's next CEO position?!

That’s the story that Silicon Alley Insider is running based on this singular tip:

I saw your recent post on Tim Cook at Apple.  I don’t know if he has been contacted yet but he is the top candidate that Spencer Stuart has identified as the next CEO of GM.  I have an inside source at Spencer Stuart.

[Interim CEO Edward E. Whitacre] wants the candidate to come from a company known for operational excellence, innovation and customer satisfaction and in addition he is looking for someone that has turnaround experience. It also doesn’t hurt that [Tim] has been able to work with Jobs. Whitacre does want to stay on as Chairman.  Also, Cook has been the key link to AT&T and should understand the culture that Whitacre,  [a former AT&T CEO] built.  

Even if Cook was chosen, would he leave Apple to run GM?  Would Apple let him go without a fight?  Seems very unlikely.