Here's the answer we got from the lizard lab:
The lizard you found is the brown color phase of the green anole. This is a very common lizard in the southeast that is often called a "chameleon" because it can change color from brown to green depending on temperature and activity level. They are generally brown when cool or inactive, so it is not surprising that the one you saw was brown at this time of year. You can learn more about this species at: http://www.uga.edu/srelherp/lizards/anocar.htm
So now we know!