WASHINGTON - The Nationals agreed to terms with closer Rafael Soriano, a person familiar with the situation said, a stunning, blockbuster addition to the back end of their bullpen.

The sides reached a two-year, $28 million contract, which makes Soriano the highest-paid reliever in baseball during the 2013 season. The contract also includes a $14 million option for 2015 that will vest if Soriano finished 120 games combined over the 2013 and 2014 seasons.

Owner Ted Lerner, one person familiar with the negotiations said, was heavily involved in bringing Soriano to Washington. Soriano is a client of high-profile agent Scott Boras, whom the Nationals have worked with to sign Bryce Harper, Jayson Werth and Stephen Strasburg, among others, to lucrative deals.

The deal shows the desire the Nationals, especially 87-year-old owner Lerner, have to win a World Series now, one year after their wrenching loss to the St. Louis Cardinals in the National League Division Series. The Nationals squandered a six-run lead after five innings and a two-run lead in the ninth inning of Game 5, and they added Soriano, 33, with the express intent of preventing another pivotal, late-game meltdown.

The Yankees, Soriano's team in 2012, gave him a one-year qualifying offer, which means the Nationals will forfeit their first-round pick - No. 31 overall - and the bonus pool money attached to the selection.

Soriano's addition bolsters the back of their bullpen, which already includes incumbent closer Drew Storen and 2011 all-star set-up man Tyler Clippard, who saved 32 games last year. It could also allow the Nationals to trade a reliever from their deep relief corps.

Soriano will presumably enter the 2013 season as the clear-cut top choice at closer, but there will still be save chances for Storen. Manager Davey Johnson believes in using an "A" and "B" closer in order to keep his best relievers healthy over a 162-win season. As the odds-on favorites to win the World Series, the Nationals should have ample save opportunities and plenty reason to keep their closer(s) fresh. Still, Storen and Clippard may have to adjust to lesser roles after dominating late-inning situations when healthy the past two seasons.

Last season, Soriano replaced the injured Mariano Rivera and saved 42 games for the Yankees with a 2.26 ERA and 69 strikeouts in 67 2/3 innings. Soriano has appeared in nine playoff games for the Rays and Yankees, allowing four earned runs over 12 innings.

For context on Soriano's vesting option, only Jose Valverde (137) and Craig Kimbrel (120) reached 120 games finished over the 2011 and 2012 seasons.