I was just cruising around Minor League Baseball's official site and noticed, for the first time ever, that they consider the Mexican League to be in Triple-A. I've never heard of any of these teams nor do any of them seem to have any affiliation with MLB clubs. What kind of talent plays there? Are they all unsigned FAs looking to make a name for themselves? Basically, what's the deal with this league and why have I never heard of it until right now?