Chatwood was activated in time to start Sunday's series finale against San Francisco.
Chatwood went 8-5 with a 3.15 ERA in 20 starts last season for Colorado. He began this year on the disabled list with a strained left hamstring.
The Rockies might need to make another roster move this week. Lefty Brett Anderson had X-rays on the injured index finger on his throwing hand after the injury appeared more serious than originally feared when he hurt it Saturday.