Farrell (oblique) struck out three of the four batters he faced and walked the other in his first rehab appearance Sunday with Triple-A St. Paul.
Farrell, who is working his way back from an oblique strain, needed 18 pitches to retire the side in what marked his first appearance at any level since June 22. He'll likely make at least one or two more appearances with St. Paul before the Twins reinstate him from the 10-day injured list.