The right-hander has been on the disabled list since the season began with a strain in the ulnar collateral ligament of his pitching elbow.
"He threw the ball pretty well in my opinion," Rockies manager Jim Tracy said. "We're trying to get ourselves into a position where we can consider a rehab assignment. I don't know whether he'll have another simulated session like we did today."
Tracy said Buchholz's command was solid, if not spectacular.
"I wouldn't go as far as to say it was pinpoint, but he certainly located some fastballs very well," Tracy said. "He threw some fastballs that were down in the zone, threw some good curveballs. He needs to get himself ... where his mind is just free of the thought that he going to encounter any type of pain in his elbow. That's something he's dealing with and something he has to get over as we go forward.
"The other thing is getting him into some game action where adrenaline comes into play and see how he responds."
JR Radcliffe is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.