(Reuters) - The Washington Nationals beefed up their pitching staff by signing All-Star free agent Edwin Jackson to a one-year deal on Thursday, the Major League Baseball team said.

Right-hander Jackson, who went a combined 12-9 with a 3.79 earned run average (ERA) in 2011 for the Chicago White Sox and World Series champion St. Louis Cardinals, will complete the move pending a physical.

Financial details were not disclosed but local media estimate the deal to be worth around $10 million.

The much travelled Jackson, 28, will join a Washington pitching rotation that includes Stephen Strasburg, Jordan Zimmermann and Gio Gonzalez.

Acquired by the Cardinals in late July, Jackson went 5-2 with a 3.58 ERA to help St. Louis clinch the National League wild card and then win the World Series in seven games over the Texas Rangers.

In a nine-year career, he has pitched for six major league teams, having had previous stints with the Dodgers, Rays, Tigers and Diamondbacks.

An All-Star in 2009, Jackson pitched a no-hitter for the Arizona Diamondbacks against the Tampa Bay Rays on June 25 2010 when he walked eight and struck out six in a 1-0 victory.

(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue; To query or comment on this story email sportsfeedback@thomsonreuters.com)