With the NFL season in jeopardy and more than $3 billion in ads at stake, TV executives are getting nervous. While Cable networks are clamoring for the $3.3 billion that goes annually to NFL games on Fox, CBS, NBC and ESPN, they’re also trying to prevent marketers from pulling money if football comes back in the fall. Upfront ad buys are not always firm, and advertisers don’t lock in until closer to the start of the new TV season when they know, for instance, their product launch dates. The flexibility to move money around early on is accepted practice. One network ad sales chief expects college football will add some $50 million in NFL money this season and baseball could also benefit, but added, “NFL is a 15 rating, and Comedy Central is a 0.7. There is nothing that can replace NFL,” according to The New York Post.