Zimmermann struck out one and held the Clippers to one hit over four innings in his second outing for the Chiefs. He faced 13 batters, inducing seven groundballs, before leaving as planned after the fourth.
The right-hander said after his final Double-A start for Harrisburg that he would likely not pitch deep into any games this season.
"I know it's a process," he said. "It'll be five [innings] and done the rest of the year, but I'll stick to the program."
Zimmermann struck out three over three hitless innings in his first Triple-A start Aug. 5. He's gone 0-2 with a 1.82 ERA, striking out 23 and walking four, in 29 2/3 innings this season with Class A Hagerstown, Class A Advanced Potomac and Harrisburg.