The NFL doesn't think it has lost viewers despite a 10 percent drop in television ratings this season.

However, Roger Goodell acknowledged that league officials are trying to understand what has caused the drop and how to address it.

"There a lot of factors to be considered. We don't make excuses. We try to figure out what's changing," the commissioner said.

"When you look at ratings you have to go deeper than that. It's viewers, but also how long they're engaging for, and a lot of times, people will leave a game for whatever reason, whether it's to go to other programming or whether the game is not that competitive."