Updated

Left-handed reliever Sean Burnett and the Washington Nationals agreed Thursday on a $3.95 million, two-year contract with a mutual option for 2013, avoiding salary arbitration.

Burnett went 1-7 with three saves and a 2.14 ERA in 73 appearances in 2010, part of a wholly rebuilt bullpen that morphed from one of Washington's biggest weaknesses to a strength last season.

He was acquired in June 2009 from the Pirates in a trade that also brought center fielder Nyjer Morgan to Washington and sent reliever Joel Hanrahan and outfielder Lastings Milledge to Pittsburgh.

The 28-year-old Burnett is 9-16 with four saves and a 3.80 ERA in four major league seasons.

His deal pays $1.4 million next season and $2.3 million in 2012. There is a $3.5 million option for 2013 with a $250,000 buyout; if the club exercises the option and he declines, there's no buyout.

The contract also includes the possibility of earning up to $500,000 each season in performance bonuses based on games finished. If Burnett finishes 35 games, he gets $100,000; for 45, another $150,000; and for 55, another $250,000.

NOTE: The Nationals announced that left-hander Aaron Thompson was claimed off outright waivers by the Pirates. Thompson came to Washington in the July 2009 trade-deadline deal that sent Nick Johnson to the Florida Marlins. In 2010, he went 4-13 with a 5.80 ERA in 26 starts at Double-A Harrisburg, and 1-0 in one start at Triple-A Syracuse.