DENVER -- With a resounding thud, the Colorado Rockies began a stretch Wednesday in which they will play 15 of 18 games at Coors Field. They received a terrific start from Tyler Chatwood, who had a career-high 10 strikeouts but let it go to waste and lost 6-3 to the Houston Astros.
The Astros pushed the winning run across in the eighth and scored three more times in the ninth.
With one out in the eighth and runners on first and second, Rex Brothers relieved Edgmer Escalona. Brothers struck out Jason Castro, but J.D. Martinez followed with a run-scoring single.
In the bottom of the eighth, Travis Blackley issued consecutive two-out walks to the two batters he faced. Hector Ambriz relieved and got Jordan Pacheco, the only batter he faced, to line out to first base with Carlos Gonzalez on deck.
"I thought that was tremendous and not letting CarGo come up with multiple guys on base," Astros manager Bo Porter said.
Troy Tulowitzki drove in Colorado's three runs, two on solo home runs, but the Rockies lost for the second time in three games this week with the Astros, the first two games taking place in Houston.
Rob Scahill, who on Wednesday began his third stint this season with the Rockies, took the mound in the ninth and gave up a leadoff homer to Carlos Pena -- his fourth of the season. Scahill had pitched 5 1/3 scoreless innings in his first two games with Colorado.
Trevor Crowe followed with a bunt single, and pinch hitter Jimmy Paredes singled with one out, sending Crowe to third. Crowe scored when Marwin Gonzalez pushed a sacrifice bunt toward first base, and Brandon Barnes followed with a run-scoring single.
"At the end," Porter said, "our ability to execute allowed us to put some distance between us and them."
While they are 16-37 overall, the Astros have gone 6-7 since May 15.
The Rockies, who stranded 12 runners and went 1-for-8 with runners in scoring position, lost for the fourth time in five games. During that span, they have gone 12-for-62 (.194) with runners in scoring position.
"If you go 1-for-8 with runners in scoring position and score only two (actually three) runs, it's difficult to win that way," Carlos Gonzalez said. "We've been playing like that for the past week and that's why we're in trouble. That's why we can't win."
The Astros came into the game leading the majors with 500 strikeouts and fanned 12 times. Nine of Chatwood's 10 strikeouts were swinging and came in six innings, after which his night ended after 96 pitches. He ran his fastball up to 94 mph and complemented it with a 78-79 mph curveball and an 86 mph slider.
His previous best was six strikeouts, done twice in 2011 while pitching for the Los Angeles Angels. The 10 strikeouts were the most by a Rockies pitcher since Christian Friedrich had 10 strikeouts on May 14, 2012, at San Francisco.
Chatwood said the key to his outing was his slider, which he and pitching coach Jim Wright had worked on in his last couple bullpen sessions.
"It's a different break than my curveball," Chatwood said, "and I just feel I can throw it as hard as I want and still have the same movement."
Chatwood allowed four hits and two runs and walked one. In addition to his 10 strikeouts, Chatwood got five outs on ground balls. Two of the three fly balls off Chatwood were sacrifice flies.
"That was frustrating," he said. "I left two pitches over the middle that they put some good swings on."
Dominguez hit a sacrifice fly in the second after Chatwood gave up a single and a double, and Castro hit one in the sixth after Chatwood found immediate trouble when Barnes led off with an infield single and took third on Jose Altuve's single.
After Castro's sacrifice fly tied the game 2-2, Altuve stole second base, but Chatwood struck out Martinez and Pena.
Chatwood's ERA actually rose slightly from 1.90 to 2.12. But in his past three starts, he has allowed one run in 17 2/3 innings with six walks and 18 strikeouts.
Tulowitzki homered in the fourth and doubled home a run in the fifth off Astros starter Erik Bedard, who went six innings and gave up seven hits with three walks and four strikeouts.
"To pitch the way he pitched," Porter said, "and be as efficient as he was in this ballpark against that lineup is pretty impressive."
Bedard has held the opposition to two runs in each of his past four starts since returning to the rotation May 11.
Tulowitzki hit his 12th homer in the ninth. It was his seventh two-homer game and first since Aug. 27, 2011, at the Los Angeles Dodgers.
NOTES: Scahill was recalled from Class AAA Colorado Springs and OF Charlie Blackmon was optioned there as the Rockies decided to go with 13 pitchers because they are in the sixth day of a stretch of 17 games in 17 days and their bullpen has been taxed recently. ... Rockies LHP Jeff Francis (left groin strain) was supposed to pitch six innings and throw about 80 pitches Tuesday in an extended spring training game against the Giants but left after 3 1/3 innings and 40 pitches when he was hit by a line drive on the front of his left ankle. Francis said he had no groin soreness while pitching and X-rays on the ankle were negative. ... Astros SS Marwin Gonzalez entered the game on a double switch in the seventh. He didn't play Tuesday due to hamstring soreness. Before the game, Porter said he preferred to give Gonzalez a second day of rest even though he had been cleared to play. But Gonzalez rode an exercise bike during the game and said he felt fine, so Porter put him in the lineup when reliever Paul Clemens took over for Bedard.