(Fast Company)  -- The tech world's getting used to the idea Steve Jobs is absent from Apple again, for medical reasons. We think he'll be back soon. But one day he won't come back, and who might fill the big chair then?





For the time being Tim Cook is in control at Apple, as he has been every time Steve Jobs has had to take time to tackle his health issues.





Cook's time in the role has, self-evidently, been highly successful, and many commenters are tipping him to be Steve's eventual successor -- with these stand-in periods acting as a carefully managed succession plan.





But is Tim really the guy for the job, given that Steve is still active as CEO in the background, and all big decisions are still cycling through him? Could someone else from inside Apple be a better fit, or is there someone working elsewhere we can imagine as the next Apple CEO?





Tim Cook





Currently Apple COO, repeat stand-in for Steve Jobs. Demanding, keen-minded, unemotional. A science and business scholar, previously at Compaq and 12 years at IBM where he managed product and manufacturing inventories and chains.





He's credited with making Apple's products stream reliably from their eastern manufacturing homes to their end users, and hot-tipped to replace Jobs by many. Recently introduced the high-profile Verizon iPhone. Once said: "Replace Steve? No, he's irreplaceable. That's something people have to get over."





Odds for replacing Steve: Long, long, long. A good temporary replacement, but lacks dynamism and creative vision.





Jonathan Ive





Currently Senior VP of Industrial Design at Apple. Highly regarded, award-winning brains behind nearly all of Apple's iconic computing and mobile products since 1996 -- starting with the industry-startling original candy-color iMac, and recently refining the aluminum unibody designs that are now a design reference point.





A highly accomplished presenter and speaker, he's known as a perfectionist and thinks focus groups are a symptom of corporate "creative bankruptcy."





Odds for replacing Steve: Medium-long, as though he's a super-hot property in the design field, and some of his philosophy aligns with Jobs', he lacks the industrial and technical training to replace his boss. He could be a powerful co-chair, though.





Phil Schiller





Currently Senior VP of Worldwide Product Marketing at Apple. A 20-year Apple veteran, in different marketing management roles, he's credited with some of the smart moves that placed iMac, iPods, and iPhones as the chic devices to own in the public's eye.





He often speaks at Jobs-led keynote speeches, and has led a keynote or two of his own to introduce new products. Not regarded as a business tiger, he does Twitter, and has spoken clearly about what makes Apple products unique: "We want things to be beautiful, surprising to see, but they also have to be functional. One without the other doesn't make any sense."





Odds for replacing Steve: Medium. He has definite genius in marketing, and shares much of Jobs' product vision. But he doesn't have a dynamic public presence, and some see him as a bad CEO -- probably better suited at staying where he is, to support any future new CEO and ensure consistency.





Scott Forstall





Currently Senior VP iPhone Software at Apple. Forstall is responsible for some of the key decisions behind Apple's OS X and its Aqua interface, and led the release of OS X Snow Leopard.





A computer scientist by training, and formerly an employee of Jobs' NeXT computer firm, Forstall reports directly to Jobs and is credited with the successful industry-defining iOS interface of the iPhone and iPad.





He's a smooth public speaker and has notable attention to detail: "I actually have a photographer's loupe that I use to make sure every pixel is right"





Odds for replacing Steve: Good. Forbes called him a name you "need to know in 2011,
Who will likely be next leader of Apple? Who is likely to be the next leader? Who is going to be the next Apple CEO?
Tim Cook Tim Cook Tim Cook
question: Who will likely be next leader of Apple?, answer: Tim Cook | question: Who is likely to be the next leader?, answer: Tim Cook | question: Who is going to be the next Apple CEO?, answer: Tim Cook