From MLB.com (1/19/2013):
"CHICAGO -- The Cubs unveiled a $300 million renovation plan for Wrigley Field, to be completed over five offseasons, and the Ricketts family will pay for the renovations if the city of Chicago will ease some of the restrictions it has placed on what the team can do with the ballpark.
The proposed changes were revealed before a standing room only crowd in a ballroom at the Sheraton Chicago Hotel & Towers, and many of the alterations were the result of fan surveys. The project would add concession stands and restrooms as well as address congestion on the concourse. The upper deck roof would be removed, and new seating platforms installed under a new roof. The lower seating bowl would have the concrete replaced and new platforms added.
There has been talk about adding a video scoreboard, but that has not been finalized. Another LED screen will be added in front of the left field bleachers; one was installed in front of the right field bleachers in 2012.
The players will benefit with the addition of underground batting tunnels behind the dugout, an expanded clubhouse, weight room and trainer's room that will include such perks as hydrotherapy machines. The Cubs currently use a batting tee and net in the home clubhouse during games."
So if they're planning on renovating Wrigley to this extent, football may not be out of the question; but it may be a few years off.