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Time is running out on the Arizona Diamondbacks in their quest for a playoff berth. At 5 1/2 games off the pace, they will try and inch closer to a postseason spot Friday in the opener of a four-game series against the Colorado Rockies at Coors Field.

The Diamondbacks were aiming for a three-game sweep of the San Diego Padres, but suffered a 6-5 loss in Thursday's series finale. Tyler Skaggs gave up a three-run home run to Jesus Guzman in the first inning and never recovered, allowing four runs and seven hits in five innings.

"He (Skaggs) gets an 0-2 count on Guzman. He tries to waste a fastball, throws it right where he doesn't want it. That is a live and learn deal," Arizona manager Kirk Gibson said.

Adam Eaton and Aaron Hill both homered, Justin Upton went 3-for-4 with two runs scored and Chris Johnson posted three hits and two RBI for Arizona, which entered the game having won five of its last seven.

Arizona will also visit San Francisco on its road trip.

Wade Miley gets the call for the D-backs tonight and is 1-2 in his last four starts. He was dealt the loss in Saturday's 3-2 setback to the Giants and yielded three runs in seven innings, falling to 15-10 in 29 games (26 starts) with a 3.10 earned run average.

Miley, who started the year 11-5 and earned an All-Star nod, is 1-0 with a 0.82 ERA in two games (1 start) against the Rockies this season. The left- hander has faced Colorado four times -- three starts -- in his career and owns a 3-0 mark with a 1.88 ERA.

Colorado enters this series having dropped six in a row and 13 of its last 15 contests. It was just swept in four games by San Francisco and suffered a 9-2 loss in Thursday's finale.

Jonathan Herrera had three hits and an RBI, Wilin Rosario finished 3-for-4 with a run scored and starting pitcher Jorge De La Rosa drove in a run for the Rockies, who will begin a seven-game homestand tonight versus Arizona and the Chicago Cubs.

De La Rosa lasted only 3 2/3 innings and was touched for six runs, five of which were earned, and seven hits. It was his first start in more than a year after undergoing Tommy John surgery.

"After 16 months, I was very pleased with what I saw from our starter today," Rockies manager Jim Tracy said. "The unfortunate thing was, we did a poor job of taking care of the baseball. We had two defensive miscues that would eventually lead to seven runs."

The Rockies are four losses from matching the worst finish in their 20-season history (67-95 in 1993 and 2005).

Rockies outfielder Carlos Gonzalez left Thursday's game before the third inning with tightness in his left hamstring and is day-to-day. He didn't start the first two games of the four-game series because of the problem.

Drew Pomeranz draws the start for Colorado tonight and is only 1-9 with a 5.06 earned run average in 19 starts this season. He pitched just three innings in Saturday's 4-3 loss at San Diego and allowed all four runs.

The left-hander faced Arizona in his season debut back on April 15 in a 5-2 loss and was touched for all five runs and nine hits over 4 1/3 frames. Pomeranz hasn't pitched well at Coors Field, going 0-5 in nine starts this season. He is 1-5 in 11 career starts there.

Arizona has beaten Colorado six times in 11 meetings this season.