Updated

The Washington Nationals and closer Rafael Soriano officially agreed to terms on a two-year contract on Thursday, adding an additional experienced arm to the back end of the defending National League East champions' bullpen.

The deal, which also includes an option for the 2015 season, was initially reported on Tuesday, with CBS Sports.com indicating the pact will be worth $28 million over the first two seasons.

Soriano comes to Washington off a very strong 2012 campaign with the New York Yankees in which the veteran righty converted 42-of-46 save opportunities after replacing an injured Mariano Rivera. He finished the season with a 2.26 earned run average over 69 appearances and struck out 69 batters over 67 2/3 innings.

The 33-year-old recorded a career-high 45 saves along with a 1.73 ERA with the Tampa Bay Rays in 2010, earning American League All-Star honors that season, and saved 27 games while a member of the NL East's Atlanta Braves the previous year.

Over 11 major league seasons with Seattle, Atlanta, Tampa Bay and the Yankees, Soriano has registered a 15-24 record with a 2.78 ERA and 132 saves over 453 career appearances, all but eight of which have come in relief. He has also held opposing hitters to a .199 batting average over the course of his tenure in the majors.

Soriano will presumably take over the closer's role from Tyler Clippard, who led Washington with 32 saves as 2011 closer Drew Storen slowly returned from an elbow injury. Storen had 43 saves with the Nationals in 2011.

The veteran hurler signed a three-year contract with the Yankees in 2011, but opted out of the deal after last season. Soriano did receive a one-year qualifying offer from New York, meaning the Yankees will receive Washington's first-round choice in the 2013 MLB Draft.