The Cubs optioned Kilian to Triple-A Iowa on Sunday, Taylor McGregor of Marquee Sports Network reports.
Kilian was ineffective in his first start of the season with the Cubs on Saturday against the Marlins, allowing seven runs on 10 hits in just 3.1 innings. The right-hander could be a starting option again for Chicago if necessary, but Saturday's outing didn't exactly inspire much confidence. Ryan Borucki was brought up from Iowa in a corresponding transaction.