State Sen. Tom Cullerton, a Villa Park Democrat, said he's exploring a run for the 8th Congressional District seat now held by Tammy Duckworth.
A run by the freshman state lawmaker would set up a primary battle against Raja Krishnamoorthi of Hoffman Estates, who says he's in the race, and fellow state Sen. Mike Noland of Elgin, who is exploring a run.
On the Republican side, Marine veteran Larry Kaifesh, who ran in 2014, has left the door open for another go.
"I know what it's like to wake up at 3 a.m., punch a time clock at 4:30 a.m. and put in a hard day's work," Cullerton said in a statement. "From the crippling cost of college to the shrinking opportunities for our next generation, I will use my blue collar work ethic to fix the problems the middle class faces."
Cullerton previously served as mayor of Villa Park and worked as a route salesman for Hostess.
In making his announcement, Cullerton touted the backing of state Sen. Tony Munoz of Chicago and Carol Stream Mayor Frank Saverino.
Duckworth has said she'll run for U.S. Senate in 2016, leaving her seat in Congress open.