This time, Atlanta will have the majors' ERA leader to counter.The Rockies' Tyler Matzek has a tough assignment Wednesday night as he will be up against the Braves' Julio Teheran, who is 3-0 against Colorado and has won four straight outings.Colorado (29-35) has dropped 11 of 12, including the first two of this four-game set which opened Monday when Christian Bergman lost his big league debut in a 3-1 defeat.Now Matzek will be recalled from Triple-A Colorado Springs to make his debut. The 23-year-old left-hander is a 2009 first-round pick who went 5-4 with a 4.05 ERA this year in the minors.Atlanta (34-29) probably won't be fazed thanks to Teheran (6-3, 1.89 ERA), whose ERA is 1.23 during his win streak. He's also among baseball's leaders in opponent batting average (.195) and WHIP (0.93).The right-hander gave up two runs in seven innings of Friday's 5-2 win over Arizona to continue the longest win streak of his career.Teheran owns a 1.00 ERA in capturing all three career starts against Colorado. The Braves have totaled 28 runs in those contests.The banged-up Rockies can't even count on any past success from NL batting leader Troy Tulowitzki against Teheran. The shortstop is 0 for 7 with four strikeouts in this matchup, and hitless in his last 10 at-bats versus Atlanta.Very little is going right for Colorado, which has dropped 15 of 18 and has injured outfielders Carlos Gonzalez and Michael Cuddyer on the disabled list. The Rockies failed to dig out of a seven-run hole after the top of the first inning in Tuesday's 13-10 defeat."It's a tough way to go," manager Walt Weiss said. "Guys fought back but we picked the wrong night to score 10. They kept battling back but it's tough to come back from that."The Braves have a fresh injury concern with Justin Upton, who left in the first inning Tuesday with a strained left hamstring. Manager Fredi Gonzalez and Upton said it wasn't serious and he could play in the next couple of days."I don't know how it's going to feel tomorrow but I'm optimistic it's not anything too serious," Upton said.Evan Gattis went 3 for 4 with four runs scored, extending his career-high hitting streak to 11 games. Andrelton Simmons hit his first career grand slam and Freddie Freeman also homered for the Braves, who had season highs in runs and hits (16) but had to hold on for their sixth victory in 10 games."Nothing surprises me in this ballpark," Gonzalez said. "I've been in this office in the same situation with a loss hanging over your head."Chris Johnson turned in his second straight three-hit effort, raising his average to .459 at Coors Field in 10 games."It's a lot of fun, especially being an offensive player and being able to bat around and score a lot of runs," he said. "Everybody's in a good mood because everyone hit and did well."