Mississippi Republican Senate candidate Chris McDaniel announced Wednesday he will run for the seat vacated by Sen. Thad Cochran, instead of challenging incumbent Sen. Roger Wicker, in an effort to “unite the party” in the double-barreled Senate race.

McDaniel, who is a Mississippi state senator, has shifted resources to campaign for the Cochran seat, which will become open April 1.

“By announcing early, we are asking Mississippi Republicans to unite around my candidacy and avoid another contentious contest among GOP members that would only improve the Democrats’ chances of winning the open seat,” McDaniel said in a statement Wednesday. “If we unite the party and consolidate our resources, we can guarantee Donald Trump will have a fighter who will stand with him.”

The seat McDaniel is now running for is the same seat he unsuccessfully competed for in the 2014 Republican primary against Cochran.

COCHRAN RESIGNATION LEAVES BOTH MISSISSIPPI SENATE SEATS IN PLAY

Cochran, R-Miss., resigned from the Senate last week amid health challenges after serving for 40 years. His seat would not have been up for re-election. His current term began after the 2014 midterm election cycle, and would expire in 2020.

But in the wake of his resignation, Mississippi Republican Gov. Phil Bryant will appoint a temporary senator to fill Cochran’s vacant seat, and a special election will be held in November.

“The governor will appoint someone to fill the vacancy,” Bryant’s spokesperson told Fox News last week. “That will happen within 10 days of April 1, Sen. Cochran’s effective date of retirement.”

It is unclear, at this point, whether Bryant will appoint McDaniel to Cochran’s vacant seat ahead of the June 5 primary run-off.

But sources told Fox News that there is some concern on the Republican side of the aisle about McDaniel—with more than one source likening McDaniel’s candidacy to that of former Alabama Republican Senate nominee Roy Moore.

"Mitch McConnell wants to hand-pick our next Senator. I understand why,” McDaniel said in a statement. “It's because they know that I won't be answering to them [GOP establishment], I'll be answering to the voters of Mississippi and putting Mississippi first."

Sources told Fox News that the GOP establishment was pushing for McDaniel to compete against Wicker, rather than for Cochran’s seat, as some members are fearful that with a McDaniel primary win, a Democrat could ultimately take the seat.

Mississippi, historically, has a long list of Democrats elected to the Senate—but this has not happened since Sen. John C. Stennis. He left his seat in January 1989—that’s almost 30 years ago.

Following Cochran’s resignation, former Rep. Mike Espy, D-Miss., announced his intention to run.

“I just learned of the pending resignation of Sen. Cochran—a person I admire and respect, and who has done so much for Mississippi over his tenure,” Espy said in a statement to Fox News. “However, now that he has announced his pending resignation, I would like to declare my strong intention to run for the United States Senate (for the Cochran seat).”

Espy, who served as a congressman from Mississippi from 1987 to 1993, was the first-African-American to hold a Mississippi congressional seat. Espy went on to serve as former President Bill Clinton’s secretary of Agriculture –the first African American to hold that Cabinet post in history.

“It’s been some time since I worked in Washington and I have witnessed with dismay the continuing dysfunction,” Espy said. “I have proven that I can work with everyone as long as the goal is a better Mississippi.”

For Wicker’s seat, there are six declared Democrats running in the June 5 primary—including the State House Minority Leader David Baria and State Rep. Omeria Scott.

Fox News' Chad Pergram and John Roberts contributed to this report.