Darren O'Day
(Nick Turchiaro/USA Today Sports)

Darren O’Day, the best free agent reliever on the market and one of the best setup men in baseball the past few years, is believed to be choosing between the Baltimore Orioles, his team for the past four years, and the Washington Nationals, who are hoping to upgrade their bullpen.

The Dodgers were once considered a suitor for O’Day but are not believed to be among the finalists. The Braves, too, are reportedly also in pursuit of O’Day, who has family in the Atlanta area.

O’Day blossomed in Baltimore and was close with Manager Buck Showalter and teammates. But the Nationals could pose a threat because of bullpen needs and because O’Day’s wife, Elizabeth Prann, is a D.C.-based reporter for Fox News.

The Nationals, however, have been reluctant to spend lavishly on free agent relievers. Bullpens are notoriously fickle and relievers break down. O’Day, a 33-year-old submarine thrower who thrives on control and deception, posted a 2.28 ERA in 2012, and then lowered each it season, reaching as low as 1.52 ERA in his all-star 2015 season. In that span, he logged at least 68 appearances each year and a combined 263 innings, the 11th most among relievers.

According to reports, O’Day is believed to be seeking a four-year deal worth around $30 million. The Nationals don’t appear willing to go to four years with O’Day. Under General Manager Mike Rizzo, the Nationals have never given a reliever more than a two-year guaranteed deal. The most the Nationals have doled out to a reliever is Rafael Soriano before the 2013 season: a two-year, $28-million deal that included a vesting option for a third year that was not reached.

This offseason, the Nationals are slowly tweaking their bullpen. The team talked to Matt Thornton, but any reunion was likely squashed with the two-year, $7-million deal reached with veteran left-hander Oliver Perez on Friday. Craig Stammen was non-tendered and David Carpenter was outrighted. For now, the Nationals believe they can bring back both Jonathan Papelbon and Drew Storen next season. Both are under team control for one more season, but both appear to be likely trade candidates. Rizzo has maintained that he wouldn’t trade either or both unless he received a good offer.

Barry Svrluga contributed to this report.