Democrat Jim Graves is dropping out of the race for Minnesota's 6th congressional district, The Hill has confirmed, leaving Democrats without a candidate for the seat to be vacated by retiring Rep. Michele BachmannMichele Bachmann'Real Housewives' producer 'begging' Conway to join cast Ex-rep admires furs amid PETA inaugural gala Why Republicans took aim at an ethics watchdog MORE (R-Minn.).

Julie Pearl, Graves' spokeswoman, said she found out Thursday night and that the decision was a "complete and utter shock" to her.

"I'm a little heartbroken. I'm one of those Democrats who's going to try to talk him back into it," she said.

Pearl wouldn't offer further details on why Graves ultimately decided against a run. But he was facing a much tougher fight following Bachmann's decision to retire, which she announced on Wednesday.

That same day, Graves sounded optimistic about his chances in the race and insisted in multiple media interviews that he planned to run as hard as ever for the seat.

“I always said I wasn’t running against Michele Bachmann, I was running for the people of the country, and that won’t change,” Graves told The Hill on Wednesday.

Graves ran against Bachmann in 2012, losing by 4,300 votes. 

Bachmann was viewed as an extremely weak candidate again in 2014, following her botched presidential bid and multiple investigations into alleged campaign finance improprieties. A recent Democratic poll showed Graves ahead by two points.

But the district is the reddest in Minnesota, and with Bachmann out, Republicans believe they have a much better chance at keeping the seat. Prior to Bachmann's retirement, it was a top target for Democrats, and considered a key seat in the party's goal of taking back control of the House.

National Republican Congressional Committee spokesman Daniel Scarpinato noted the fact that Graves' exit from the race complicates Democrats' efforts to take back the House.

“Another Democrat recruitment failure to add to the ever-growing list. This is exactly the kind of district Democrats need to win in order to have any shot at winning the majority, and even their own candidates know that’s nothing but Nancy Pelosi’s fantasy," he said.

But the Democratic Congressional Campaign Committee isn't giving up on the race yet, according to spokeswoman Emily Bittner.

“We expect this district will feature a bitter Republican primary fight over who can get the furthest to the right the fastest, and we’ll monitor the race as it develops. Regardless of whether Michele Bachmann is running, her brand of extremism and obstruction has infected the Republican party – and it will be on the ballot in MN-06 and Republican-held districts across the country where we will fight to elect commonsense problem-solvers," she said.

Graves wouldn't say whether the realities of the fight ahead informed his decision, but he told the MinnPost, which broke the news, that he felt with Bachmann retiring, he had accomplished what he set out to do in running for Congress.

“Basically, after all that’s gone on, and with Michele Bachmann now stepping down, I’ve been talking to my friends and family and frankly, the feeling is, ‘Mission Accomplished,'" he said.

"She wasn’t representing the people of the 6th District appropriately, and now she won’t be representing them. There’s no way anyone could run and win who would be worse than Michele Bachmann. So we accomplished that task.”

--This piece was updated at 1:01 p.m. to reflect comment from the DCCC and NRCC.