I swore I read something where he said that although not seriously hurt, that competing in absolutes over the years has given him random aches and pains, and that he just didn't feel the drive to want to do it anymore. I think 2007 was his best performance even though Drysdale ended the party in the absolute final. But 7 subs in 7 matches while debuting the guillotine and north south choke was awesome. Marcelo even joked and said he still got 8 submissions in all 8 matches, but that "the 8th submission was me tapping." Such a cool spirit to have.
That ADCC (2011) was crazy with the constant weigh ins. Frankly I don't know how some people did it. Ryan Hall came in and wondered "Did I do this right?" he looked so tiny and gaunt, but Rafa Mendes was walking around at the same weight not only looking healthy, but totally ripped and swole. Marcelo looked big for 169.5 and I wonder if you know, did he have a hard time making weight on day 2? I heard some people did but got passes anyways, like Palhares.
I don't know if they had the same policy at ADCC 2013, because there was no press, but I'm guessing they did?
Here's a Marcelo highlight from ADCC 2011 for the hell of it. Making it look easy out there.
https://www.youtube.com/watch?v=O-5HCG7wC2s