Rockies catcher Yorvit Torrealba was scratched from Thursday's game against the Arizona Diamondbacks and replaced by Chris Iannetta.
Colorado says Torrealba is being evaluated by the medical staff for an undisclosed injury.
The team also announced during the game that it had purchased the contract of catcher Adam Melhuse from the Triple-A Colorado Springs Sky Sox.
Melhuse hit .317 with three homers and 14 RBIs in 29 games with the Sky Sox.
The Rockies optioned outfielder Cory Sullivan to their top farm club to make room for Melhuse.