The Diamondbacks had a four-game winning streak snapped and suffered a blow to their hopes of catching the Los Angeles Dodgers in the NL West. Los Angeles began the day with a 3 1/2-game lead over the Diamondbacks.
De La Rosa (9-8) allowed a run on three hits with six strikeouts, sending the Rockies to their fourth win in five games after having dropped seven in a row.
Arizona sent highly-touted prospect Max Scherzer to the mound and he remained winless in the majors. Scherzer (0-3) gave up three runs on seven hits in six innings. He struck out seven.
The loss was Arizona's 11th straight on the road.