It's based off of Sheilla dingus's analysis of recent CA2 cases. i hope this helps! according to her, there ahave been 21 en banc petitons filed since april 25 that CA2 is still deciding. it seems like this is a very conservative court procedure-wise, so they will likely issue their decision in order of receipt. brady filed his en banc appeal end of May, so probably we'll hear something late August. i don't think they will make a special exception for brady and the nfl.
Second Circuit Update: 7/11/16
Good post, that explains the time frame.