A top aide to retiring U.S. Sen. Dan Coats could become the first person to formally jump into the race to take his place.
Former Indiana Republican Chairman Eric Holcomb has scheduled a Thursday announcement about the 2016 Senate campaign.
Several possible Republicans and Democrats have been mentioned or expressed interest as possible candidates since the 71-year-old Coats, a Republican, announced Tuesday he wouldn't seek re-election.
Holcomb has been chief of Coats' Indiana offices since stepping down in 2013 after nearly three years as GOP chairman. He previously was a top adviser and campaign manager for then-Gov. Mitch Daniels but hasn't held elected office before.
In addition to Holcomb, State Sen. Mike Delph, R-Carmel, said Wednesday that he was "interested in considering this opportunity."
On Thursday, U.S. Congressman Todd Young, a Republican from the 9th Distict, said he would also consider running for the seat.