Former Indiana Sen. Evan Bayh is expected to announce a run for Senate on Monday, sources told CNN .

Former Rep. Baron Hill, the current Democratic nominee, informed the Indiana Democratic Party chairman Monday morning that he is dropping out of the race.

“While our campaign had been making great progress and building momentum all over Indiana, it is simply not enough to fight back against the slew of out-of-state special interest and dark money that is certain to come our way between now and November,” Hill said in a statement.

Hill has struggled to raise money, and ended the first quarter of 2016 with $449,000. Bayh, meanwhile, has $9 million sitting in his campaign account. Democrats had tried to recruit him for the race over a year ago, but he passed.

“Baron Hill has always put Indiana first, and has been focused on setting aside party differences to strengthen our state and country. I share this commitment, and agree with him that the stakes have never been higher,” Bayh said in a statement Monday.