Even his mom Debbie didn't know what her son was going to do.
Debbie Phelps: It's like, "Come on, you know, do you want to do this? Do you want to go an extra four years?" That's a long time.
Anderson Cooper: But you hoped he would go forward?
Debbie Phelps: Absolutely.
Michael Phelps: It was hard, because I didn't know if the passion or the fire was still inside of me. And it took awhile for me to actually realize it myself. Bob couldn't tell me, my mom couldn't tell me. They couldn't help me find it.
It didn't help when in January 2009 newspapers around the world published a photo of Phelps with a marijuana pipe. The photo tarnished his image.
Michael Phelps: I mean, that was probably like the lowest point in my career. I think being able to see how it affected the close people around me, I think that was the thing that hurt the most.
Anderson Cooper: How do you mean?
Michael Phelps: Just, you know, telling my mom that. I don't ever want to tell her something like bad like that that happened
Debbie Phelps: I asked my three-letter word, "Why?" Or, "What were you thinking? Who were you with?" It's like, "Come on Michael. Get with the program here."
Michael Phelps: It was just stupid. You know, it, it, I put myself in a bad position. And I probably went through like a huge like depression phase, where I was just like, "What am I doing?"
While paparazzi staked him out, Phelps was suspended from competition for three months by USA Swimming.
Michael Phelps: I would do nothing. Like, I would just wake up at you know 11:00 o' clock in the afternoon. Just wouldn't leave the house. And sit around, play video games. I was so lazy.
It wasn't until March of 2009 that Phelps came to a decision about the London Olympics.
Michael Phelps: I don't know what it was, I don't know what struck it. But I just woke up one morning and I was like, "Let's do it."
[Bob Bowman: One minute, take it from the top...]
Yet even after announcing he was a go for London...
[Bob Bowman: Get in, just get in...]
Phelps seemed to stick only a few toes in the water.
[Bob Bowman: Get in!]
He regularly skipped practices, unheard for Phelps, who as a teenager went six straight years without missing a single day of training. His apathy infuriated his coach Bob Bowman.
Anderson Cooper: When he was missing in practices, was it, he would just miss one or two?
Bob Bowman: Oh no, I think the fall of 2009, he missed months.
Anderson Cooper: Months?
Bob Bowman: Maybe six weeks.