The decision means Chacin (0-3, 7.30 ERA in five starts) still has a Minor League option. If he's not optioned this season, the Rockies can send him down to the Minors in a future year without exposing him to other clubs via waivers.
A drop in velocity and lack of action of his pitches out of his hand raised suspicions that Chacin was injured. In a meeting with manager Jim Tracy, Chacin said his pitches didn't feel right, but he didn't say he was in pain. An MRI revealed no structural damage, but the Rockies' staff has noted inflammation and will give that time to heal.
"We've got to get him quieted down so we can get him back out there and pitching," Tracy said. "It's in the shoulder/biceps area. It's not anything really specific, but there's some inflammation."
Chacin, in a statement through his publicist, said he will have time to figure out what's wrong.
"I don't know [what] the rehab process will be like, but the fundamental thing ... will be to strengthen both my shoulder and biceps with several exercises," Chacin said. "It is the very same thing that affected me during Spring Training, and that could be the cause behind my velocity being diminished.
"My arm has not felt the same way whenever I pitch. Not even my breaking pitches have had the same effect as they used to, and that could be a consequence of this weakness in my arm."