Mayor Rahm Emanuel is a strong advocate of pursuing a Super Bowl, but Soldier Field currently seats just 61,500 and would be considered too small by NFL standards to host the annual championship game.
The mayor's office is working with the Chicago Park District, the owners of the stadium, on the feasibility of such a project.
"It's an exploration to see what, if anything, is possible," Emanuel spokeswoman Sarah Hamilton told the Chicago Tribune.
The smallest stadium to host a Super Bowl was the Metrodome in Minneapolis with an attendance of 63,130 in 1992. The NFL mimimum is considered 70,000 seats, which means a 5,000-seat expansion in Chicago would fall short of that.
Emmanuel told the Tribune in February that the city might bid for the Super Bowl by 2019.
"The goal is to find a decision that moves the city forward," Emanuel said. "You don't measure it that way. Would a Super Bowl be good for the city and good for the NFL? I think yes. Would having the NFL draft here be good for the city and for the NFL? The answer is yes. The goal is to have a discussion."
The NFL showed its openness to holding a Super Bowl in a cold weather city when the game was played last month in Met Life Stadium in New Jersey.
The Chicago mayor's office did not indicate a cost for the project or how it would be funded.