DENVER -- Rockies left-hander Jorge De La Rosa left his most recent start victorious but vexed.

De La Rosa held the D-backs to two hits, but walked six in five innings of a 13-5 victory Sunday. Although De La Rosa didn't get some close calls, he acknowledged something was wrong. He just didn't know what.

Now that he has watched tape and visited with pitching coach Bob Apodaca, he understands his problems are no different from the ones he has overcome before. He hopes to straighten himself out with his next start, Friday against the Padres in the opener of a three-game set and a nine-game, 10-day road trip.

It's the last extended road trip of the season for the Rockies, who lead the National League Wild Card race by 4 1/2 games over the Giants and trail the NL West-leading Dodgers by two games. De La Rosa, who is 14-3 with a 4.03 ERA since the start of June, is one reason for the success.

Now that he knows why he struggled in his latest start, he is confident he can continue to be a pitching leader.

"'Dac' and I in the bullpen were working on staying back," said De La Rosa, who has made the same adjustment on the fly during some of his successful starts. "I think I was jumping toward the plate. So we tried to fix that."

PETCO Park is often considered heavenly for pitchers, not that De La Rosa can't necessarily concur. He went six innings and gave up three runs (one earned) on three hits in a Rockies victory there May 4. However, De La Rosa's throwing error led to two runs.

In three career games at PETCO, including one start, De La Rosa is 0-1 with a 4.70 ERA.

"I didn't throw that well when I pitched there," De La Rosa said. "But every game is different."

Pitching matchup
COL: LHP Jorge De La Rosa (14-9, 4.51 ERA)
De La Rosa has more wins than any pitcher since June 1, so it could be said his turnaround is a complete one. But De La Rosa also has been spending time looking at film of his last start, a win but a rough performance. De La Rosa hasn't had the best of luck against the Padres this season -- 0-1, 5.06 ERA in three starts. Of course, all of those were in April and May, before he caught fire.

SD: RHP Edward Mujica (3-4, 3.51 ERA)
This spot would have normally gone to rookie Mat Latos, but the Padres have shut him down after he threw 123 innings this season. So the team will bump everyone back a day to get them extra rest and give this start to long reliever Mujica, who nearly got a spot start earlier this season before Clayton Richard arrived to take it. The team will, obviously, need some relief help, which could mean the Major League debut of left-hander Cesar Ramos, a possibility to follow Mujica to the mound.

Tidbits
Rockies reserve Mike McCoy, who made his Major League debut Wednesday night after eight Minor League seasons, struck out looking at a 3-2 pitch from the Reds' Kip Wells on Thursday to end his first Major League at-bat. McCoy had played 859 games in the Minors. ... The Rockies gave first baseman Todd Helton a day off on Thursday. His wife, Christy, had given birth to the couple's second child on Wednesday. ... Rockies outfielder Seth Smith has 21 RBIs in his past 17 games.

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Up next
• Saturday: Rockies (Esmil Rogers, Major League debut) at Padres (Tim Stauffer, 4-6, 3.49), 8:05 p.m. MT
• Sunday: Rockies (Jason Marquis, 15-10, 3.65) at Padres (Clayton Richard, 8-5, 4.88), 2:05 p.m. MT
• Monday: Rockies (Jason Hammel, 8-7, 4.31) at Giants (TBD), 8:15 p.m. MT