Referring to Bruyneel's book, Lance and Bruyneel are winners. Anything other than winning is not acceptable. If Lance returns, he must believe he can win. Otherwise, it will be similar to other so called comebacks that in many ways tarnished professional athletes' records. Unlike golf, this is no masters pro tour.
Bruyneel portrays Lance as having much more capability than he allowed him to use in winning the 7 TdFs. There were specific races where Lance was told to hold back. One of my favorite examples of this was a race up Alpe D'Huez. Bruyneel wanted Lance to let a credible racer but not a contender win the stage. As Lance is going through the motions of appearing to chase the lead group he radios Bruyneel that he could beat these guys on a tricycle. Assuming it is true, Lance is very tough. His retirement was more about "Hey, I am tired of the grind to do what is necessary to win. He is a smart guy and although nothing is certain, he must believe he can do what it takes to win....again. Welcome back.