Lopez was hit hard by Chicago on Tuesday, giving up six runs and three homers while recording just two outs. He has an 11.37 ERA in four games.
Manager Walt Weiss says he wants Lopez to get to the point where he "believes in his sinker and is able to make it dive to the bottom of the zone."
Rutledge hit .389 in five games at Colorado Springs. He's insurance with shortstop Troy Tulowitzki bothered by tightness in his right quadriceps. Weiss plans to play it safe with Tulowitzki and gave him the day off Wednesday.