Tennessee state Sen. Jim Tracy (R) is set to announce his candidacy for Rep. Bart Gordon's (D-Tenn.) seat, according to a source with knowledge of his plans.

The source said Tracy plans to make his announcement Monday. Gordon announced moments ago that he would not seek reelection. Tracy has been seriously considering the race.

Tracy, who did not immediately respond to requests for comment, would give the GOP a top-tier recruit in the race. But with an open seat in a strongly conservative district, he is unlikely to be the only Republican in the race.

Gordon's seat will vault to the top of the list of pickup opportunities. It went strongly -- 62-37 -- for Sen. John McCain (R-Ariz.) last year. Gordon didn't face a GOP opponent, but an independent candidate took 26 percent of the vote against him.

Former Rutherford County GOP Chairwoman Lou Ann Zelenik and activist Dave Evans are already running on the GOP side. Zelenik, in particular, could provide a well-funded challenge to Tracy.

It's so far unclear who the Democrats will be looking at for the race. But they have been making preparations in the state for another vacancy in Rep. John Tanner's (D-Tenn.) district, and Gordon's retirement isn't terribly surprising.

UPDATE: Potential Democratic candidates include state Rep. Mike McDonald, Wilson County Sheriff Terry Ashe, state Rep. Hank Fincher and former state Sen. Andy Womack.