Weiss, 51, had been dealing with two days of stomach discomfort and the team says he left Angel Stadium with head athletic trainer Keith Dugger before Wednesday’s game against Los Angeles for a follow-up exam and soon after had surgery.
The Rockies begin a four-game series against the Dodgers on Thursday.
"As far as I know, from what the trainers told me, he had some surgery on his appendix," Rockets bench coach Tom Runnells said. "It went well. He's resting. He's going to L.A., but probably out of commission for a couple of days."
Runnells managed the team on Wednesday, a 2-1 defeat to the Angels, their 11th straight loss. Colorado (11-19) is tied for the second worst record in the National League.
Runnells will also lead the team on Thursday, as their is no timetable for Weiss’ return.
Weiss is in his third season with Colorado and has complied a 151-202 record.
- Scooby Axson