Chatwood (8-4, 3.15 ERA), the Majors' road-ERA leader (among pitchers qualified for the official ERA lead) at 1.25, gave up three runs on four hits and an uncharacteristic three walks before leaving Saturday's 9-6 loss to the Marlins. The Rockies came back and took a lead before losing it, so the defeat went to Chatwood's replacement, righty Eddie Butler -- who is expected to replace Chatwood in the rotation.
Chatwood said Monday he has been undergoing treatment and feels better. He will return to Denver, rather than accompany the team to New York for a two-game series with the Yankees.
"I thought I'd try to battle through it, but toward the end there, I thought I was going to hurt something else if I kept going," Chatwood said. "I'd never felt it [before].
"I didn't want to go out there and not pitch. Anytime I can pitch, I'm going to try to. Looking back at it, it probably wasn't the best thing to try to do, but luckily we caught it before anything else happened."
An injury is no positive, but the bright side is it can preserve some wear on Chatwood's arm. He has thrown 85 2/3 innings in 14 starts. Chatwood underwent Tommy John surgery on his right elbow in 2014 and didn't pitch last season, so the Rockies are conscious of his innings load. Chatwood also underwent Tommy John surgery in high school.
"It was something we were paying attention to during the season, to pick a spot to give him some rest," manager Walt Weiss said. "Maybe this is that time."
Righty Scott Oberg replaced Chatwood on the Major League roster Sunday and threw two scoreless innings in a 3-0 loss to the Marlins. On Monday, the Rockies optioned Oberg back to Triple-A Albuquerque and recalled righty Jordan Lyles -- a starter-type whom the Rockies want in a long-relief role.
Thomas Harding has covered the Rockies since 2000, and for MLB.com since 2002. Follow him on Twitter @harding_at_mlb, listen to podcasts and like his Facebook page. This story was not subject to the approval of Major League Baseball or its clubs.