Kyle Kendrick and Jordan Lyles are scheduled to start the final two games against the D-backs.
The date to make up Sunday's game with the Giants will be announced later.
The Rockies will make a roster move before the game Monday, which begins a six-game road trip that will conclude with three games at the Padres.
Reliever Jorge Rondon arrived from Triple-A Albuquerque on Sunday morning. The Rockies did not announce the corresponding move necessary to add Rondon to the 25-man roster before Sunday's game with the Giants was postponed and will do so Monday.
The Rockies claimed Rondon, 27, off waivers from the Cardinals in November. At Albuquerque this season, Rondon had no record and a 1.35 ERA in five games while holding opposing batters to a .095 average. In 6 2/3 innings, he has allowed two hits and two walks with four strikeouts.
Rondon went 5-4 with 10 saves and a 3.03 ERA last year for Triple-A Memphis and pitched in one game for the Cardinals, working one scoreless inning against the Dodgers on June 29 at Los Angeles.
"I like that he throws about 98 [mph]," manager Walt Weiss said. "He's one of the power arms that we brought in in the offseason. He's been pitching well down there in Albuquerque. [He] got a cup of coffee in the big leagues with the Cardinals. [He's got a] very big arm, talented pitcher, so we're looking forward to seeing what he looks like."