DENVER -- The Milwaukee Brewers, hoping their second-half woes are behind them, will begin a formidable 10-day, nine-game trip Friday at Colorado.

After three games against the Rockies, the Brewers will continue playing National League West foes, with stops at San Francisco and Los Angeles.

The starters Friday are Milwaukee's Matt Garza (6-6, 4.38 ERA) and Colorado's German Marquez (9-5, 4.13).

The Rockies (67-54) and Arizona Diamondbacks (67-54) are tied atop the National League wild-card race, with the Brewers (63-59) sitting 4 1/2 games behind. Milwaukee has won four straight, a winning streak preceded by a six-game losing streak.

The Brewers went into the All-Star break with a 5 1/2-game lead in the NL Central but has since gone 13-18 to slip a game behind the Chicago Cubs. Since the break, the Brewers are 4-11 on the road.

The Brewers and Rockies began the season at Miller Park, with Colorado winning three of four games. The Brewers are 12-13 against the NL West and 4-7 against the Rockies, Giants and Dodgers.

The Rockies have lost seven of their past 10 games overall but are 37-23 at home. The Dodgers, quite simply, are a juggernaut at a major-league-best 85-34. And while the disappointing Giants have the second-worst record in the NL, the Brewers are 22-36 all-time in San Francisco and last won a series there in 2010. So Milwaukee's trip won't be easy.

"There's a challenge every single night," Brewers manager Craig Counsell told the Milwaukee Journal Sentinel. "It's, 'Play a good game.' I think if we play a good game, we have a really good chance to win. That's how you look at it.

"The schedule is something totally out of our control. It's in front of us the next day. The schedule says, 'Be here. This is who you're facing.' That's how you have to treat it."

Garza is 2-5 with a 6.10 ERA in seven career starts against the Rockies and 0-3 with an 8.82 ERA in three starts at Coors Field.

The Brewers are 9-9 in games started this year by Garza, who won his last start 7-4 Sunday against Cincinnati while giving up five hits, five walks and four runs (three earned) in 5 1/3 innings. Garza has not pitched six innings in any of his past six starts.

Marquez's four-game winning streak ended Sunday at Miami, where he allowed seven hits and five runs in 4 1/3 innings as the Rockies fell 5-3. Colorado is 12-8 in starts by Marquez, who is 5-0 with a 2.72 ERA in his past seven starts at Coors Field and 0-0 with a 3.00 ERA in one start against Milwaukee last year.

Rockies first baseman Mark Reynolds will be facing his former team this weekend.

In his one season with the Brewers in 2014, Reynolds hit just .196 with 22 homers and 45 RBIs in 130 games. However, the 34-year-old veteran has been a difference-maker this year in his second season with the Rockies.

In December, Colorado signed Ian Desmond to a five-year, $70 million contract to play first base. On Feb. 1, the Rockies signed Reynolds to a minor league contract, with the intent of having him provide right-handed power off the bench.

However, Desmond opened the season on the disabled list with a broken left hand and is on the disabled list again with a right calf strain. He has played just 65 games, more in left field than at first base.

Reynolds, meanwhile, is hitting .280 with 25 homers, 80 RBIs and an .880 OPS in 113 games.

"The thing I'm most proud of is I took advantage of an opportunity," Reynolds said. "I don't wish ill on anyone, but unfortunately Desi got hurt and I was able to kind of cement myself in the lineup.

"I remember I first talked to (manager) Buddy (Black) when I signed, and I told him, 'I know the situation. My main goal is to make it hard on you to take me out of the lineup.' And I'm really proud of myself that I was able to stay consistent and produce, and like I said, take advantage of the opportunity I was given."