MacIver is expected to miss the first 6-to-8 weeks of Triple-A Albuquerque's season after he recently received an anti-inflammatory injection in his right shoulder, Thomas Harding of MLB.com reports.
MacIver was pegged to serve as Albuquerque's primary backstop to begin the season, but the injury will likely keep him on the shelf until around late May or early June. The Rockies signed Grayson Greiner to a minor-league deal Tuesday to bolster their catching depth at Triple-A.