This is the second injury Chatwood has sustained this week, though it's more serious. During his sprint work Saturday in Pittsburgh, Chatwood experienced left hamstring tightness. The team scratched him from Tuesday's start, choosing to give him extra rest.
If there were no other setbacks, the plan was for him to start Thursday.
Colorado manager Walt Weiss said Chatwood threw a bullpen session on Wednesday to test the hamstring, but another problem cropped up.
"He came in today and he had inflammation in his elbow," Weiss said.
Chatwood has been one of the Rockies' most reliable starters this season. The 23-year-old is 7-4 with a 3.15 ERA in 15 starts.
This isn't the first time this season Chatwood has experienced pain in his arm. He was taken out after four innings during his start against the Reds on June 3 because of soreness in his right triceps. He was given extra rest and made his next start on June 15, but he didn't need a trip to the DL.
The Rockies are currently 1-8 since leaving Denver last week and have dropped four straight games, but they would've had one of their top pitchers on the mound to try and stop the skid.
"Tyler's been real good. When it rains, it pours," Weiss said. "That's a guy you'd love to run out there when you're struggling like we are."
Chris Iseman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.