According to NBC, the Pro Bowl did a 7.7 overnight rating. If that number holds up, that will top the 7.6 rating (12.2 million viewers) for game one of the World Series.
To be fair, this should not be an indictment of the popularity of baseball. Baseball is much more of a regional sport than the NFL. More than 74 million tickets were sold to Major League Baseball games in 2012. In 2011, the NFL sold just slightly more than 17 million. However, it does show that baseball fans tune out if their team is not involved, while football fans will literally watch anything as long as there is a football involved.
One reason for the national appeal of football is the gambling. According to Darren Rovell, there was as much betting action on the Pro Bowl as the NBA's two biggest games on Sunday combined (Heat vs Celtics, Lakers vs Thunder).