PHOENIX -- The Rockies are not ready to name a replacement for Tyler Chatwood in the starting rotation, but Jhoulys Chacin appears to be the top option.
Chacin, who has recovered from a strained right shoulder, completed his rehab assignment and appears on track to return to the big leagues Sunday against the Mets. Chacin allowed one run on four hits in six innings in a rehab start for Triple-A Colorado Springs on Tuesday against Memphis.
"It's hard to say because we are several days away, but it looks like the natural fit," Rockies manager Walt Weiss said. "Jhoulys has to be re-evaluated, too. He just made a start, and he's going to have to throw a side and go through the routine that he has in between starts and make sure that he's OK."
Chacin went 1-1 with a 2.53 ERA in 10 2/3 innings over two games at Triple-A. He also pitched two games for Class A Advanced Modesto during his rehab stint.
"It's difficult to think four or five days ahead in this game because things chance on a daily basis," Weiss said.
Jesse Sanchez is a national reporter for MLB.com. Follow him on Twitter @JesseSanchezMLB. This story was not subject to the approval of Major League Baseball or its clubs.