What's a "reviewable play"??

The list of plays I know to be reviewable are:

1. Did the ball cross the goal line / hit the pylon?

2. Where should the ball be spotted by the official?

3. Was a ball fumbled by the ball-carrier or down by contact?

4. Was a ball fumbled by the QB before passing or was it an incomplete pass (The Brady "tuck rule")?

5. Did a receiver have possession of the ball to make the catch (if heading out of bounds) or before fumbling the ball?


There are more, but the big things that can't be reviewed tend to be flags and official rulings that whistle the ball dead, like someone going out of bounds like Calvin Johnson was alleged to have done.