On Wednesday, Sept. 5, former President Bill Clinton is scheduled to give one of the most anticipated speeches of the Democratic National Convention, during which time he’ll formally offer President Obama for re-nomination.  But how many Americans will actually be paying attention?

In an unfortunate bit of timing for Democrats, Clinton’s prime-time speech to the delegates will conflict with the NFL’s opening game, between the defending Super Bowl champions, the New York Giants, and their division rivals, the Dallas Cowboys. Given that the (at least) three-hour game is slated to start at 8:30 p.m. eastern time the event will take up the entire prime time period. It will also mean the Clinton speech won’t be broadcast live on NBC, which is airing the game.

One theoretical option for the Democrats would be to move the Clinton speech to 7 p.m. — but that would push him out of prime-time and mean it would air at 4 p.m. on the West Coast. Also, Massachusetts Senate candidate and liberal hero Elizabeth Warren is supposed to speak before Clinton, so such a move would push her remarks even earlier. Last year, the White House moved Obama’s jobs speech to 7 p.m. so as not to conflict with the NFL opener, and it was the lowest-rated address to a joint-session of Congress of his presidency.

The NFL opener typically occurs on a Thursday. In 2008, when the game coincided with Sen. John McCain’s speech to the Republican National Convention, the NFL started the game at 7 p.m., and McCain still drew record ratings for a convention speech. But this year, instead of moving the game to an earlier time Thursday, the league moved it to Wednesday so as not to conflict with Obama’s acceptance speech.

An important factor to keep in mind is not just raw viewership, but how the time conflict might affect the types of viewers who will be watching Clinton. For instance, those who think Clinton’s speech is more compelling television than NFL football might already be committed Democrats intending to vote for Obama anyway. Whereas less partisan viewers who choose to watch football instead might be exactly the type of swing voters that Clinton’s speech would hope to appeal to. The widespread use of DVR devices and online streaming video might make this conflict less meaningful than it might have been in another era, as football fans could always watch the game and catch the Clinton speech later. Still, it’s a conflict Democrat convention organizers would have probably prefered to do without.