To say that this iguana is a Yankees fan, or is at the game to see A-Rod, supposes two things:
1. The iguana chose to wear this jersey (he almost certainly did not).
2. Lizards like baseball.
On No. 2, that is surely false. The iguana is a genus of herbivorous lizard native to Mexico, Central America, many Polynesian islands and parts of the Caribbean. As such, it is much more likely that it is a soccer fan, and would rather be wearing a New York Red Bulls kit, or even more likely, the jersey of the Honduras National team.
Or, the NBA, as long as the team is in Florida. The particular specimen below looks much more natural.
Or even more likely: he prefers cricket.