Juan Nicasio will undergo arthroscopic surgery on his left knee to remove a loose body that is causing inflammation and fluid to build up.
The Rockies are hoping to have Nicasio ready to go come September.
Nicasio, 25, has made 11 starts this season with a 5.28 ERA, but peripherals suggesting much better production than his traditional numbers suggest.
This will put additional pressure on the current Rockies' rotation to stay healthy and productive, as well as on the long relief, currently embodied by Tyler Chatwood and Carlos Torres. With Jorge De La Rosa likely out for the season and Chacin still yet to begin a rehab assignment, the current depth is basically Alex White and Josh Outman who were just recently demoted to AAA Colorado Springs due to poor performance.
An additional blow may come in the next few weeks, as the Rockies are still looking to trade Jeremy Guthrie.