From what I am reading it is vialble cash and not on the book cash.
http://sports.yahoo.com/nfl/news;_ylt=As1euPqo9ujcqPQz9v6X8PNDubYF?slug=ap-nfllabor
A lengthy new CBA—between six and eight years, for example—would enable the league to turn to its broadcast partners and negotiate more...