Webb, 22-7 with a 3.30 ERA last season, won the NL Cy Young Award in 2006 and was the runner-up each of the past two seasons. He was to see the Diamondbacks' team doctor Wednesday and will not throw for at least two days, Melvin said.

Webb gave up six runs and six hits in four innings Monday and complained of soreness after the game, saying his shoulder stiffened during the D-backs' long third inning rally in which they scored four runs to take a 6-4 lead.

Webb gave up back-to-back home runs to Troy Tulowitzki and Chris Iannetta opening the Rockies' fourth.

After playing catch Tuesday, Webb reported no pain, but he arrived in the clubhouse Wednesday morning with soreness in his right shoulder, Melvin said.

Webb felt shoulder soreness once during spring training, Melvin said, adding that diagnostics have not been done.

Right-hander Yusmeiro Petit will start Saturday in place of Webb against the Los Angeles Dodgers. Petit was 3-5 with a 4.31 ERA in 19 appearances last season, including 3-4 with a 4.35 in eight starts.

ROCKIES 9, DIAMONDBACKS 2: Stephen Drew's first-inning home run was about the only offense the D-backs could muster against Colorado LHP Franklin Morales and three relievers. Arizona had four other hits, all singles, and did not score again until there were two outs in the ninth. The D-backs had two runs and 10 hits in the final two games of the series after hitting five home runs in a 9-8 victory in the season opener. LHP Doug Davis gave up a homer to Dexter Fowler leading off the game and three more runs in the fourth inning.