(SportsNetwork.com) - Arizona righty Josh Collmenter tries to beat the Colorado Rockies for the second time in less than a week on Tuesday when the National League West rivals open what is now a two-game series at Coors Field.

This series was slated to get going on Monday, but rain caused the contest to be postponed. No makeup date has been announced.

Collmenter won for the second time in three starts on Wednesday, as he held the Rockies to an unearned run and five hits over eight innings. He also struck out five and did not walk a batter to improve to 2-3, while lowering his ERA to 2.76.

"You know what? He keeps the ball off the barrel," Rockies manager Walt Weiss said. "He adds and subtracts, changes eye level. He knows how to pitch and he pitches off the barrel."

Collmenter has faced the Rockies 19 times (9 starts) and is 3-1 against them with a 3.59 ERA.

It was a rough weekend for Arizona, which dropped all three games to the Los Angeles Dodgers, including a 1-0 setback in 13 innings on Sunday.

In the top of the 13th, the Diamondbacks had runners at first and third, the first time a runner had reached third all game. A pitch from J.P. Howell (1-1) then got away from Yasmani Grandal. Jordan Pacheco raced home, but Grandal was able to recover and toss the ball to Howell, who brought his glove behind the back to tag out Pacheco.

"I had a good jump, I took a chance. J.P. did a good job of covering the plate," Pacheco said.

Grandal then clubbed a leadoff home run in the home half of the frame to send the Diamondbacks to their seventh loss in nine tries.

Colorado, meanwhile, was also swept this past weekend and has dropped five in a row following an 8-6 setback on Sunday to the San Diego Padres.

Kyle Kendrick (1-4) was charged with the loss after giving up six runs on six hits in five innings on the hill.

Nolan Arenado homered twice among his three hits and drove in three for Colorado, while Charlie Blackmon also hit two homers in the loss.

"We need to get better," said Arenado. "We need to do everything -- pitch better, hit better with men on base. All around, we are not very good right now. We need to start changing it up because losing gets contagious and people start to get out of it. We need to start winning."

Hoping to stop the bleeding for the Rockies on Monday will be lefty Tyler Matzek, who had to leave his last start with a hamstring issue. Matzek, though, still picked up the win in Arizona last Monday, as he held the D-backs to a pair of runs and five hits in five innings. He is 2-0 on the year with a 2.70 ERA.

Matzek is 2-1 in three starts versus the D-backs with a 2.65 ERA.

Arizona took two of three from the Rockies last week at Chase Field.