Williams's comments to Kentucky Sports Radio on Wednesday were his first since a scathing state audit of the department two weeks ago of Farmer's eight years as agriculture commissioner.
WFPL quotes Williams as telling Kentucky Sports Radio he chose Farmer, a former University of Kentucky basketball star, because he was the most popular political figure in the state at the time.
Republicans Williams and Farmer lost to Democratic Gov. Steve Beshear and running mate Jerry Abramson in November.
The state auditors discovered what they said was misuse of state resources during Farmer's administration.