U.S. Sen. Sherrod Brown, the highest-ranking elected Democrat in the state, is endorsing U.S. Rep. Tim Ryan’s bid to join him in the Senate.

Brown, D-Cleveland, will make the announcement today during a news conference in his hometown, several sources close to Ryan’s campaign said.

Ryan’s Senate campaign issued a statement Tuesday saying the candidate and Brown would “discuss what’s at stake in Ohio’s U.S. Senate race next year.”

Brown, a longtime political ally of Ryan, is expected to campaign for the candidate with a stop expected shortly in the Mahoning Valley.

Brown joins the only two other Democrats serving in Congress from Ohio, besides Ryan, to endorse the 10-term House member for the open Senate seat.

Previously, U.S. Rep. Joyce Beatty, D-Columbus and the chairwoman of the Congressional Black Caucus, and U.S. Rep. Marcy Kaptur, D-Toledo and currently the longest-serving woman in the House, endorsed Ryan, D-Howland, for Senate.

Incumbent Sen. Rob Portman, R-Terrace Park, announced Jan. 25 that he wouldn’t run next year for re-election, citing “partisan gridlock” as a reason.

Ryan has received the endorsements of more than 200 current and former elected officials and Democratic leaders in the state as well as 19 labor unions and the Ohio AFL-CIO.

Brown, who is serving his third term in the U.S. Senate, was the lone holdout among the Ohio congressional delegation until now.

Brown said in August that he had “great confidence” in Ryan, who was someone who “stands up for working people and is always fighting for the people who make this country work.”

William Binning, retired Youngstown State University political science department chairman, said the Brown endorsement “is very important” for Ryan.

“Democratic elected officials and donors looking for cues now have it with Brown’s endorsement,” Binning said. “It gives the Democratic political establishment a direction. It’s going to help Tim significantly.”

Ryan’s campaign last week announced he had raised $2.5 million in contributions between July and September, showing a steady increase in each of the year’s three quarters.

Ryan, a 10-term House member, has raised about $6 million toward his Senate campaign since the start of the year and had $3.6 million in his fund as of Sept. 30.

Morgan Harper, an attorney and community organizer who is also running for the Democratic nomination, announced her candidacy Aug. 18. She raised $533,147 between her announcement date and Sept. 30, according to her campaign.

Several Republicans are running next year for the Senate seat.

As of Tuesday, the only Republican to announce the amount raised in the third quarter was Jane Timken, a former Ohio Republican Party chairwoman. Timken’s campaign said last week it had raised $1.7 million in the third quarter and had more than $3.1 million in her campaign account as of Sept. 30.

Businessman Mike Gibbons, another Republican candidate, hasn’t disclosed how much he raised in the third quarter, but said last week he gave $2.25 million more to his campaign. He gave $5.67 million to his campaign in the second quarter.

Senate candidates have until 11:59 p.m. Friday to file third-quarter reports with the Federal Election Commission, but often announce the amounts they raise — particularly if they have strong numbers — before the deadline.