By PAUL DIGIACOMO
(AP) -- The Arizona Diamondbacks had a golden opportunity to keep pace in the race for the NL's second wild-card spot the last time they took the field.
But their failure to come through in the clutch instead pushed them further back in the playoff hunt.
Arizona looks to bounce back Friday night when it visits the Colorado Rockies in the opener of a four-game wraparound series.
The Diamondbacks (74-75) had a chance to complete a three-game sweep of San Diego and win their fourth straight Thursday, but they fell 6-5 after failing to score in the bottom of the ninth inning despite having the bases loaded with no out.
That defeat coupled with St. Louis' 5-4 victory over Houston dropped Arizona 5 1/2 games behind the Cardinals for the second wild-card berth.
"All things considered we battled back," manager Kirk Gibson said. "You get the bases loaded and nobody out in the ninth, you expect to at least tie the game up. We had three opportunities and were unable to do it, so that part was disappointing."
Facing last-place Colorado (58-91) for four games could help the Diamondbacks make up some ground. The Rockies have lost six in a row and 13 of 15 overall, and Arizona has won four of the last five matchups.
Rookie of the Year candidate Wade Miley (15-10, 3.10 ERA) starts the opener for Arizona, looking for another dominant performance against the Rockies.
The left-hander pitched three scoreless innings of relief in Colorado on April 14 before allowing one run and three hits while walking none over eight innings of a 6-1 home win June 6. Miley is 3-0 with a 1.88 ERA in four career appearances - three starts - against the Rockies.
However, he enters this matchup struggling. Miley is 1-2 with a 4.85 ERA over his last four starts, with Arizona losing three of them. Despite throwing 177 innings in his first full season in the majors, Gibson doesn't think Miley is wearing down.
"Everybody says just shut him down but what if he has to go 230 next year, or 240," Gibson said. "He has prepared his whole life to become a major leaguer. This has been his dream. He has worked his way to being a starter for us.
"He has been as consistent a pitcher for us as anyone on our staff and we don't see any things right now that would lead to (shutting him down)."
Miley will be pitching against a Colorado team that scored seven times in a four-game sweep at NL West-leading San Francisco, losing 9-2 on Thursday.
The Rockies also lost left fielder Carlos Gonzalez after the first inning due to a lingering left hamstring injury.
"I've pulled the leg before, so it's nothing," said Gonzalez, batting .304 with 22 homers and 85 RBIs. "I just have to wait until it feels good again before I play a game."
Colorado will send Drew Pomeranz (1-9, 5.06) to the mound, and the left-hander will be trying to end a 12-start winless stretch. Pomeranz is 0-6 with a 6.52 ERA since winning at Washington on July 6.
He was roughed up in his only career start against the Diamondbacks on April 15, allowing five runs and nine hits over 4 1-3 innings of a 5-2 home loss.
Updated September 20, 2012