"He'll eat up innings for us," said Twins Manager Ron Gardenhire. "Our bullpen worked a lot of innings in the first week of the season."
Mulholland was 3-4 with a 4.91 ERA with the Cleveland Indians in 2003. He allowed just five of 28 inherited runners to score and his 81 1/3 innings ranked ninth among relievers in the American League.
A 17-year veteran, Mulholland has a lifetime record of 119-131 with a 4.37 ERA.
The Twins designated lefthander Brad Thomas for assignment to make room for Mulholland.
Aaron Carter is still in love with Hilary Duff
NBC reportedly holds celebs hostage to Jimmy Fallon's show