Chacin, 24, looked like a budding star the first three months of last season, his first full season in the Majors, but he has gone 3-13 since last June 27. He looked lost at times on Tuesday, to the point where manager Jim Tracy asked him on Wednesday if he was injured.
The answer to that question wasn't clear. Chacin indicated that he feels good but that there's something different about his delivery.
"There is nothing physically wrong, but the ball's not coming out [of his hand]," Tracy said. "We've seen pitchers go through this before. We're definitely dealing with a situation like that. He's talked about the fact that he throws the pitch and it doesn't feel like it's coming out [correctly]. 'Are you hurt?' 'I'm not hurt.' We have to move forward, keep investigating and figure out a way to skin this cat, because we need this guy."
Pitching coach Bob Apodaca is as much at a loss as anyone.
"I was very optimistic about him going into last night's game," Apodaca said. "His preparation was very good during the week. He was in a good frame of mind. He expected himself to go really deep into the game. He was confident. He got punched in the mouth in the first inning, and what happens is that he pitched to avoid further damage, went away from trying to get quick contact.
"He's a little dazed right now. He's searching. I wish it was just one mechanical thing that is the problem. He's going to have to enjoy some success and gain some confidence that he doesn't have to make perfect pitches."
As for who will replace Chacin, there are myriad options at Colorado Springs.
Right-hander Alex White (1-2, 2.92 ERA) struggled in a loss at Sacramento on Tuesday night, giving up three runs (two earned) and running up such a high pitch count that he was removed after 4 2/3 innings. He hasn't pitched more than six innings in a game.
Righty Tyler Chatwood started the year in the Rockies' bullpen and is building up his arm for starting duty.
Left-hander Christian Friedrich had his moments in Spring Training and is 2-1 with a 2.59 ERA at Colorado Springs. However, his last start, in which he allowed two runs in five innings in a no-decision against Fresno on Sunday, came after he had missed 13 days with an injury to his left hamstring.
The Rockies have already turned to Colorado Springs once, calling up righty Guillermo Moscoso (0-1, 10.80 ERA) after Jeremy Guthrie went on the disabled list with an injured right shoulder. Moscoso will start on Friday night against the Braves in the opener of a three-game set at Coors Field.
Even with the lack of ready-made answers, the Rockies decided that Chacin will have to work out his troubles in Triple-A.
During the winter, general manager Dan O'Dowd questioned Chacin's conditioning program in Venezuela, but Apodaca insists Chacin is in proper shape. He even said Chacin's usual problem of developing blisters on his pitching fingers hasn't arisen.
"I'm just going to keep working, trying to get better," Chacin said after Tuesday's game, when it wasn't clear if he would be demoted. "I'm not going to give up."