"The thought process behind this is that we're trying to get him [pitching on shorter rest] on somewhat of a regular basis," manager Jim Tracy said.
Chacin (right shoulder inflammation) has been on the disabled list since May 2 after beginning the season 0-3 with a 7.30 ERA. He used his full complement of pitches on Tuesday, throwing 30 during a simulated game -- 15 per inning. The Rockies expect Chacin to add an extra inning -- 15 pitches -- while sticking mostly to his hard stuff as he focuses on command of his fastball, which plagued him in five starts this year.
Tracy expects Chacin, whenever he returns, to rejoin the starting rotation.
"We'll have to wait and see how he does, how much volume he can take on, especially early on," Tracy said, noting Chacin will have to improve his recovery ability. "We'll see how he bounces back from each [simulated game]. His arm strength seems to be in the direction you'd want to see it moving in, so it's safe to say he passed that test.
"If he has a setback, we'll reel him back in. but right now, we're trying to move him forward."