(Reuters) - The Minnesota Twins added some power to their lineup by signing free-agent outfielder Josh Willingham to a three-year deal worth $21 million, the Major League Baseball (MLB) club said on Thursday.

Willingham, 32, hit just .246 last season for the Oakland Athletics but set career highs in home runs (29) and runs batted in (98).

The signing indicates that the Twins are unlikely to retain their own free agent outfielders, Michael Cuddyer and Jason Kubel, with speedsters Denard Span and Ben Revere expected to hold down two outfield spots.

Right-handed hitting Willingham, a career .262 hitter who spent two seasons with the Washington Nationals from 2009-10 after playing his first five MLB seasons with the Florida Marlins, has topped 20 home runs four times.

(Reporting by Larry Fine in New York; Editing by Frank Pingue)