More information on it? Sounds interested.
Its like a virtual card game, with the cards being players and they have overall ratings. You field an entire team, every position (except punter) and play games against the computer or friends. The games are simulated and for every scoring play it'll show a screenshot of two random teams doing something (handoff, catch, interception, field goal). You gain experience points and money from games. Experience goes towards your level (like COD) and you can use money to upgrade your stadium, buy card packs to try and get better players, or buy other random stuff.
You use "tickets" to be able to play a game in a season. They replenish over time and by gaining a level, and you never get more than 5.
The weekly predictor was the funnest part of the whole thing. Picking NFL games against friends and then bragging about who did better.
Just another one of those facebook games that you'll waste time on. I quit after week 4. Still do the predictor though.