Former Rep. Pete Hoekstra (R-Mich.) will challenge Sen. Debbie Stabenow (D) next year, a Republican source confirmed to Roll Call on Tuesday.

His candidacy is a boost to Michigan Republicans after several well-known GOP candidates passed on challenging the Democratic incumbent.

“He’s a very strong candidate who guarantees this seat is in play,” former Michigan GOP Chairman Saul Anuzis said.

Hoekstra had ruled out a Senate bid this year, but his former campaign aide recently told Roll Call that he was reconsidering.

Hoekstra told MIRS News on Monday that his decision would come “very, very quickly.” The same Michigan news outlet first reported that he would enter the race.

Hoekstra left Congress after nine terms and ran for governor in 2010, but he lost the GOP primary to now-Gov. Rick Snyder.

Democrats immediately attacked Hoekstra’s nascent campaign Tuesday.

“Mr. Revolving Door — Pete Hoekstra is a Congressman turned Washington lobbyist who has stood up for taxpayer-funded bonuses for bailed-out CEOs, tax giveaways for oil companies, and Republican efforts to privatize Medicare,” Democratic Senatorial Campaign Committee spokesman Shripal Shah said in a statement. “After his party rejected his bid for Governor, Hoekstra is now shopping for another revolving door to pass through.”

Some lesser-known Republicans have jumped in the race against Stabenow, including Oakland County Water Resources Commissioner John McCulloch. But Bill Ballenger, a nonpartisan Michigan political analyst, said Hoekstra would easily be the frontrunner in the GOP primary.

However, Ballenger cautioned that Hoekstra could struggle to compete with Stabenow on the fundraising front. She reported $4.1 million in the bank at the end of last month.

“One problem for Hoekstra is that he’s never been good at fundraising,” Ballenger said. “Hoekstra is simply going to have to get that kind of financial support from the national party or the state to have a real chance against Stabenow.”