The Phillies released Zeuch on Saturday.
The Rockies reassigned Zeuch to minor-league camp Monday.
Zeuch signed a minor-league contract with the Rockies on Tuesday.
Zeuch (back) was released by the Reds on Wednesday.
Zeuch was placed on the 15-day injured list Thursday with back soreness.
Zeuch (0-3) took the loss Wednesday, allowing six runs on seven hits and four walks over 2.2 innings against the Phillies.
Zeuch is scheduled to start Wednesday's game in Philadelphia, Bobby Nightengale of The Cincinnati Enquirer reports.
The Reds recalled Zeuch from Triple-A Louisville on Tuesday.
Zeuch was optioned to Triple-A Louisville on Saturday.