HOUSTON -- Josh Willingham, whose 61 home runs over the past three seasons are the most by any Twins player, has been traded to the Kansas City Royals two months before his contract was to expire, the team announced shortly before game time Monday.

In exchange for the 35-year-old outfielder, the Twins receive righthanded pitcher Jason Adam, a 23-year-old native of Overland Park, Kansas, who has been pitching this season for Class AAA Omaha. Adam, a fifth-round selection in the 2010 draft, has been a starter throughout his career until reaching Triple-A, where he has posted a 2.35 ERA in eight appearances as a reliever. Adam will be assigned to Class AA New Britain.

The Twins used Willingham's roster spot to activate Joe Mauer from the disabled list. Mauer is in the lineup tonight for the first time since suffering a strained oblique muscle on July 1.

Willingham smacked 35 home runs in 2012, his first season after signing a three-year, $21 million contract with the team. But like Kevin Correia, who was dealt to the Dodgers on Saturday, he was unlikely to remain with the Twins beyond this season, so he was traded to a contender. The Royals, who have won seven straight games, currently lead the race for the second AL wild-card spot.