My first instinct is to say, "I'll believe it when I see it," but according to The Daily Caller, this isn't impossible:

In the city of Chicago itself, he retains a 60-29 lead over Romney. But the Republican challenger leads 45-38 in the surrounding areas. Across the county as a whole, Romney leads 43-31 among independent voters, a crucial voting bloc. ....

Illinois is not considered a swing state by any means; it is seen as solidly blue, and has been for the past two election cycles. But McKeon pointed to the 2010 gubernatorial race when Republican Bill Brady came within a single percentage point of now-Gov. Pat Quinn because Brady won most of the downstate counties. That is a feat Romney could repeat this year, leaving Obama vulnerable if he cannot expand his lead in Cook County.

I would like to point out that this is a poll of registered voters, not likely voters, so I would be hesitant to draw too many conclusions from it. At the same time, if Obama is having enthusiasm problems in Chicago, that doesn't bode well for the campaign. Even Walter Mondale won his home state.