If Tim Cook is the new Steve Jobs, who is the new Tim Cook?

Tim Cook, as has been well documented, has some pretty big shoes to fill as CEO of Apple. But one of his first tasks may be to fill the role he has vacated. His successor will have almost as much to live up to in that role as Cook has in his new job.

In the thirteen years since Cook left his short stint at Compaq for life (and it really was life, rather than just a job) in Cupertino, he and his team revolutionised the way Apple worked, tearing apart its manufacturing processes and re-building them using contractors, negotiating deals with supply chain partners, and driving down inventory levels. Cook played a huge part in Apple’s success over the last decade.

So who will succeed him? Writing in the Wall Street Journal’s All Things Digital blog, John Packowski makes a great case for Jeff Williams, effectively Cook’s number two in his role as senior vice president of operations. ‘It was Williams, for example, who orchestrated Apple’s massive flash memory purchase in 2005, one that effectively cornered the market for NAND flash and left rivals scrambling for supply. He’s also credited with leading worldwide operations for the iPhone since the device first launched,’ wrote Packowski.

That’s not a bad couple of lines to have on your CV.

Not all big companies have COOs, however, and it may be that Cook doesn’t feel he needs one immediately. Steve Jobs did the job alongside that of CEO for several months, because, as he told Business Week, ‘I couldn’t find anyone internally or elsewhere that knew as much as I did.’

If he decides not to fill the COO role, Cook will surely have to find a replacement for retail chief, Ron Johnson, who announced in June that he would be leaving Apple for department store, JC Penney. Johnson was responsible for the launch and growth of Apple’s retail stores, and with dozens of stores due to open around the world in the next couple of years, including 20 in China, a replacement is surely a priority.