Farrell was recalled from Triple-A Iowa on Monday, Carrie Muskat of MLB.com reports.
He has a 9:1 K:BB in 5.2 MLB innings this season, but has given up five runs over that stretch. Farrell has been more effective (4.94 ERA) albeit less dominant in the strikeout department (24 strikeouts in 23.2 innings) as a starter at Triple-A. He will serve as a long reliever, and could piggyback starter Mike Montgomery on Monday.