Willingham has been out since he was hit in the left wrist by a pitch Sunday in Cleveland. The move would be retroactive to Monday, and the Twins plan to fill his roster spot with right-hander Michael Tonkin.
Assistant general manager Rob Antony says Willingham took batting practice before Friday night's game against Kansas City and still felt pain when he swung hard. Antony added that Willingham might be sent for another MRI exam Saturday.
Willingham, who had 14 homers and 48 RBIs in 111 games last year, is hitting .294 in six games this season with no home runs and one RBI.
Tonkin appeared in nine games for the Twins last season, allowing one earned run in 11 1-3 innings.