WASHINGTON — Sen. Bob Corker, R-Tenn., isn't running for re-election but he had many words of praise Wednesday for the Democratic candidate who is trying to replace him. 

Phil Bredesen, the former Democratic governor, is running in a tight race against Republican Rep. Marsha Blackburn for the open Tennessee senate seat.

Corker has donated money to Blackburn but said he won't campaign against Bredesen.

"I worked very closely with him for years, and he was a very good mayor, very good governor, very good businessperson and look, I'm not going to campaign against someone who, you know, I've been a friend with and worked with," Corker told reporters at a breakfast hosted by the Christian Science Monitor. 

In candid comments, Corker said Bredesen is receiving the support of Republicans in the state. 

"Will Bredesen have cross-over appeal? No question. I mean, we have significant Republican fundraisers who are hosting fundraisers for him today, so there's no question he's going to have cross-over appeal," Corker said. 

Blackburn's campaign spokesman Abbi Sigler didn't react specifically to Corker's comments, but said, "Phil Bredesen will be a solid vote for Chuck Schumer and Obama, Clinton-era liberal policies, and Tennesseans are not interested in that."

Blackburn entered the race after Corker, who was fed up with President Donald Trump and politics, said he wouldn't run for re-election. But Corker openly floated changing his mind, even after Blackburn had declared her candidacy. 

Corker added on Wednesday: "I usually don't give money to candidates I don't plan to vote for, but we'll see."

Vaughn Hillyard contributed to this story.