Ross Detwiler made his second start of the season for Washington on Thursday night and did reasonably well. The Nationals' offense, however, did little until it was too late, and their bullpen faltered in a 6-3 loss to the Colorado Rockies.

Detwiler had made five long relief appearances since his first start July 5. He pitched five innings, gave up five hits and two runs and left trailing 2-1.

"I didn't think he had real good command of his breaking ball," Nationals manager Davey Johnson said. "He threw pretty good fastball-changeup, didn't use his breaking ball a whole lot. I thought overall he did a pretty good job. Good-hitting ballclub and a tough ballpark. For coming out of the pen it was acceptable."

Esmil Rogers started for the Rockies, taking the spot in the rotation that Ubaldo Jimenez occupied before he was traded to Cleveland on Saturday. Rogers relieved Jimenez that night in San Diego and allowed one run in five innings. Against the Nationals, Rogers gave up seven hits and one run in 5 2-3 innings and threw 112 pitches.

"I felt like we let him off the hook numerous times," Johnson said. "He's got a good arm, but he made a lot of bad pitches and we just didn't capitalize."

The Nationals scored a run in the first when Rogers gave up a leadoff single to Rick Ankiel and with one out walked Ryan Zimmerman, who extended his hitting streak to 13 games and went 3 for 4 with two RBIs. Rogers gave up a run-scoring single to Michael Morse, but Rogers got Jayson Werth to fly to deep center and struck out Laynce Nix.

Washington had a runner on second with two outs in the second, but Ankiel flied out. Zimmerman doubled off the right-field wall with one out in the third. But Morse grounded to third, and after Rogers (5-1) hit Werth with a 1-2 pitch, Nix struck out.

The Rockies broke a four-game losing streak. The Nationals lost for 10th time in their past 13 road games as they began a 10-game trip. They are 32-23 at home but just 21-35 on the road.

Detwiler held the Rockies hitless for three innings, allowing one runner to get to second base in that span. But the Rockies pushed across single runs in the fourth and five on five hits. Detwiler (1-1) walked Todd Helton with one out in the fourth and yielded three straight singles, the second a run-scoring hit by Ty Wigginton. Chris Iannetta led off fifth with a double and after Rogers' sacrifice, Iannetta scored on Eric Young Jr.'s single.

"I started walking people and was leaving the ball up a little bit," Detwiler said. "They were able to get under it and put it in the outfield."

After his 66-pitch effort, Detwiler was relieved by Collin Balester in the sixth. Troy Tulowitzki, the first batter he faced, hit his 21st homer to give the Rockies a 3-1 lead. Tulowitzki went 3 for 4 and finished a triple shy of the cycle. Balester worked two innings before Johnson brought in Ryan Mattheus, who began his career in the Colorado organization and was traded to the Nationals in a two-for-one deal for reliever Joe Beimel in July 2009.

"I thought the right guys were coming in there," Johnson said, "and Mattheus, I forgot we got him from the Rockies. He was too pumped up. He came out there just wired, can't do that."

The Rockies batted around and scored three runs in the eighth off Mattheus, who had allowed four runs in his previous 23 1-3 innings in his first 22 games in the majors. He gave up two hits, three walks, one intentional, and hit a batter. Mattheus gave up a bases-loaded single to Chris Nelson for the first run of the inning, hit Iannetta with a 1-2 pitch with the bases loaded and issued a bases-loaded walk to Young during a 36-pitch inning that included just 17 strikes.

"I didn't put anything extra on it, I don't think," Mattheus said of pitching at Coors Field for the first time and facing the Rockies. "I just didn't throw very many strikes and you can't do that up here at this level. Guys are going to get you if you fall behind in counts. I gave four guys free passes out there — three walks and another hit batter.

"I faced these guys before at our ballpark. I don't think I was extra hyped or tried to get guys out any more than I normally would."

The Nationals were down to their last strike when Zimmerman doubled home two runs against closer Huston Street in a non-save situation. Street ended the game by getting Morse to fly to right.

Notes: Nationals RHP Stephen Strasburg is scheduled to make his first rehab start Sunday with Class A Hagerstown. He threw a successful side session Thursday at the Nationals' spring training complex in Viera, Fla., two days after pitching in a simulated game there. Strasburg is recovering from Tommy John surgery on Sept. 3. ... Nationals C Ivan Rodriguez had a setback in his recovery from a strained right oblique and will not begin a minor league rehab assignment over the weekend, Johnson said. Rodriguez will visit Dr. Bill Meyers in Philadelphia for a second opinion. The Nationals backup C, Rodriguez, 39, has been on the DL since July 7 and was expected to begin a rehab assignment over the weekend with Hagerstown. ... Zimmerman is hitting .446 (25 for 56) during his 13-game hitting streak with five doubles, three RBIs and nine runs scored and has had eight multi-hit games during the streak.