After winning the NL pennant a year ago, the Rockies (63-72) had been one of the biggest disappointments in baseball as they went into the All-Star break with the third-worst record in the league (39-57). They've managed to get their season back on track, however, as they are tied with Houston for the NL's third-best record (24-15) since the break.

Colorado was nine games out of first on Aug. 14, but has since won nine of 12 to pull within six of NL West-leading Arizona. The Padres (51-82), owners of the second-worst record in the league, have assisted the Rockies in the standings, as San Diego capped a three-game sweep of the Diamondbacks with a 5-4 victory Wednesday.

A win for Colorado in Friday's opener coupled with an Arizona loss to Los Angeles would pull the Rockies within five games of first place for the first time since April 21.

Colorado's latest surge is reminiscent of last season, when it won 14 of its final 15 regular season games, including a one-game playoff against the Padres, to clinch the NL wild card.

"That seems to be the reality of it, but it's not the game plan," Rockies manager Clint Hurdle told the team's official Web site. "We're disappointed in the way we played earlier. Now there's nowhere else to look and somehow we've found a way to respond to the challenge. I don't know whether to laugh or cry."

Colorado scored 22 runs during a four-game winning streak before losing 4-1 to San Francisco on Wednesday.

The Rockies and Padres have split their 12 meetings this season with each team winning three times at home.

While San Diego's playoff chances are virtually gone, it scored 18 runs in its sweep of the Diamondbacks after plating 21 in losing its previous seven games.

"At this point, we'll probably be spoilers," said Jody Gerut, who had three hits and drove in the go-ahead run Wednesday. "We want to make the other team sweat a little bit."

Gerut and the Padres try to win four straight for the first time since July 25-28 as they face All-Star Aaron Cook (15-8, 3.91 ERA), who has been bothered by lower back tightness and is in a bit of a funk.

The sinkerballer is 1-2 with a 6.75 ERA in four starts this month, and has failed to get past the sixth inning in any of those outings. On Saturday, Cook gave up four runs and eight hits in five innings of a 7-6 win over Cincinnati, but was not a factor in the decision.

Cook yielded six runs and 10 hits in 5 2-3 innings in an 8-3 loss to the Padres on Aug. 9. He had allowed one run and eight hits over 16 innings in winning his first two starts of the season against them. The right-hander is 8-2 with a 2.05 ERA in 12 starts versus San Diego since 2004, including 4-1 with a 1.50 ERA in six starts at Petco Park.

The Padres counter with Dirk Hayhurst (0-0, 6.75), who makes his second career start.

In his major league debut on Saturday, Hayhurst allowed three runs and five hits in four innings of San Diego's 4-3 loss to San Francisco. The right-hander was pulled after 76 pitches. He had made two starts in 46 appearances for Triple-A Portland this season.