"It's an exploration to see what, if anything, is possible," Emanuel spokeswoman Sarah Hamilton said late Tuesday.
Last month, the mayor told Tribune sports columnist David Haugh that Chicago could bid for the Super Bowl as early as 2019.
“The goal is to find a decision that moves the city forward. 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,” Emanuel said.
Chicago houses the NFL's smallest stadium in terms of capacity. Soldier Field seats 61,500 -- 8,500 shy of the NFL's preferred minimum for a Super Bowl.
“We'll work with that footprint,” Emanuel said last month. “It's all a process.”
The NFL held a Super Bowl in a cold weather city last month at Met Life Stadium in New Jersey, which holds more than 82,000.
According to Hamilton, the mayor's interest in possibly adding more seats to Soldier Field has as much to do with getting more revenue out of the Chicago Park District-owned lakefront stadium for other events like concerts or the outdoor NHL game last weekend between the Blackhawks and Pittsburgh Penguins as it does Chicago's longshot Super Bowl bid.
"The mayor always wants to explore options to see what is possible, this is the same. It's an exploration, nothing more," Hamilton said.
It's unclear how much adding the seats would cost, or how it would be paid for. Moody's just downgraded Chicago's credit rating, which would make borrowing money more expensive for the city.
In 2001, a new state law allowed the Illinois Sports Facilities Authority to issue bonds for renovations at Soldier Field — changes that then-Mayor Richard Daley and others said were needed to keep the Bears in Chicago.
At the time, the agency provided more than $400 million toward the $600 million project, which included some money for work at U.S. Cellular Field.
The ISFA increased its debt, but the city agreed to cough up the extra money if hotel tax revenue fell short. Soldier Field reopened in 2003, but cost overruns made the total for the entire project about $690 million, and a Tribune analysis showed the public portion was actually $432 million.
In 2001, The Illinois Sports Facilities Authority sold $399 million in bonds to finance Soldier Field's reconstruction, with revenues from the hotel tax collected in Chicago used to retire the bonds. Any shortfall were to be covered by the city's share of the state income tax.
There is no timeline on a Soldier Field expansion, since officials from the city and Park District are at this point simply looking into whether this is something they want to pursue.
When NFL Commissioner Roger Goodell visited Soldier Field in 2012, the mayor leaned on him to have a Super Bowl in Chicago. Goodell acknowledged then that Soldier Field's relatively small capacity could be an issue.
That total was increased to about 68,000 for the 2012 Super Bowl, according to the NFL. Lucas Oil Stadium also has a retractable roof.