Rusin (shoulder) was placed on the 15-day disabled list Tuesday, Patrick Saunders of the Denver Post reports.
The left-hander had already been scratched from his next scheduled start earlier in the day Tuesday, and the Rockies have since decided that Rusin will require a stint on the DL. According to Saunders, Rusin is battling a shoulder strain, so it's unclear exactly when he'll be ready to resume throwing. The Rockies recalled reliever Miguel Castro to add bullpen depth in a corresponding move Tuesday, but they'll still need to make a decision on who will step in to start in Rusin's place Friday.