Sanders, who has been crisscrossing the country raising money and speaking to supporters, appeared at an event for mayoral candidate Jesus "Chuy" Garcia and Susan Sadlowski Garza, a candidate for alderman.
"If I fall asleep up there the reason is that I was in L.A. and I was in Las Vegas and I was in Texas and here now," said Sanders. "We have just had huge turnouts. What I am trying to ascertain: whether or not there is the support all over the country for a movement like this. And we have done very, very well on this trip."
Sanders declined to set a hard deadline for himself to reach a verdict.
"We will make the decision when we have to make the decision," he said.
Garcia is running to incumbent Mayor Rahm Emanuel's left in a contentious runoff campaign that will culminate in a Tuesday election. Garcia, like Sanders, has routinely expressed concerns about the gap between the rich and the poor.
The senator said he was not going to disparage Emanuel, though he expressed worries about the mayor receiving campaign donations from wealthy contributors.
"I'm not here to campaign against Rahm Emanuel. I've known Rahm for many, many years. I am here to campaign for Chuy and Susan," he said.
In a fiery speech with his sleeves rolled, Sanders explained why he thinks addressing income inequality is so crucial. He also called for expanded education funding. a higher minimum wage and revamping campaign finance laws to prevent wealthy donors from dominating elections.
"We need to forge a new relationship between the federal government, state government and local government," said Sanders.
As he mulls a presidential run, Sanders, who would start as a heavy underdog against former secretary of state Hillary Rodham Clinton should they both seek the Democratic nomination, said he is closely considering whether he will be able to raise enough money to be a real factor.
"The Koch brothers probably are not going to contribute to me," he quipped.