A pair of left-handers make their major-league debuts when the Colorado Rockies host the St. Louis Cardinals on Wednesday in the rubber match of their three-game series. St. Louis' Marco Gonzales, who grew up in Fort Collins, Colo. - some 60 miles from Coors Field, opposes Yohan Flande. "A lot of guys come in here (Denver) not knowing what to expect,'' Cardinals manager Mike Matheny told the Denver Post about pitching at altitude. "But this is something (Gonzales) grew up with.''Colorado snapped its seven-game losing streak with a 10-5 victory on Tuesday behind the red-hot Justin Morneau, who belted a three-run homer among his three hits and drove in a season-high six runs. Morneau, who has 13 RBIs in his last five contests, is the only player in the majors this season with three games of five or more RBIs and has 57 overall, trailing National League leader Giancarlo Stanton of Miami by one. St. Louis' Matt Holliday, who played the first five seasons of his career with the Rockies, went 2-for-5 for the second straight game to improve his career average to .360 at Coors Field - .545 in the last five contests.TV: 3:10 p.m. ET, MLBN, FSN Midwest (St. Louis)PITCHING MATCHUP: Cardinals LH Marco Gonzales (NR) vs. Rockies LH Yohan Flande (NR)Gonzales went 3-2 with a 2.33 ERA while striking out 46 over 38 2/3 innings in seven starts with Double-A Springfield of the Texas League - and was a combined 5-4, 1.89 in 13 outings with Springfield and Single-A Palm Beach in 2014. "I didn't have too many expectations (this year),'' the 22-year-old told the Denver Post. "I just wanted to compete. That's the biggest thing for me, and the rest kind of takes care of itself.'' Gonzales originally was drafted by the Rockies in 2010 before opting to attend Gonzaga. His father Frank - a former minor-league pitcher - is pitching coach at Tri-City, Colorado's Class A affiliate in the New York-Penn League.Flande takes the place of rookie Christian Bergman, who broke his left hand on a comebacker Friday in his third major-league start and is expected to miss at least six weeks while becoming the fourth Colorado starter to appear on the disabled list this season. Flande pitched professionally since 2006 with two organizations previously - Philadelphia and Atlanta - and advanced as high as Triple-A with the Braves. The 28-year-old Dominican, who becomes Colorado's major league-high 12th starter in 2014, was 2-9 with a 4.42 ERA while allowing 82 hits and 26 walks and striking out 52 in 71 1/3 innings with Triple-A Colorado Springs.WALK-OFFS1. Rockies OF Corey Dickerson is 15-for-30 with two homers and six RBIs in his last seven games.2. St. Louis SS Jhonny Peralta on Tuesday homered for the first time in 14 games - his team-leading 11th.3. Colorado is 7-15 in June.PREDICTION: Cardinals 9, Rockies 8