Caleb Kilian threw pretty well in his first MLB start, but has struggled since then, including Monday night against the Pirates.
With Kilian sporting a 10.32 ERA and 2.029 WHIP in 11x MLB innings (with 13 walks), the Cubs opted to option him back to Triple-A Iowa to get some more starts in against Triple-A hitters.
Alec Mills, who threw four-plus innings (and 74 pitches) in relief of Kilian Monday night in Pittsburgh, will likely take Kilian’s rotation spot, which will next come up Saturday in St. Louis.
To replace Kilian on the active roster, righthander Mark Leiter Jr.