City hall sources tell ABC7 there will be an announcement Thursday concerning Commissioner Hoff's future, but there's no confirmation yet he's resigning.
Hoff has been with the department for more than 30 years. He was appointed to the commissioner's post by former Mayor Richard Daley.
Firefighter's union president Tom Ryan said he had no idea why Hoff is stepping down.
"We may have had our differences on some certain subjects along the way but I have nothing but the utmost respect for Commissioner Hoff and I wish him well in whatever he decides to do," said Ryan.
Hoff did not return ABC7's calls.
The mayor's office would not confirm nor deny Hoff's reported retirement.