The Rockies' Eric Young Jr. steals second as Nationals shortstop Ian Desmond bobbles the ball during the seventh inning. (Jack Dempsey/AP)

The Washington Nationals started their road trip fast Thursday night. The first batter the Nationals sent to the plate scored. Ross Detwiler, their starting pitcher, recorded 10 outs before he allowed his first hit. But their night unraveled from there, as tends to happen for the Nationals when they play away from home.

With their 6-3 loss to the Colorado Rockies, the Nationals dropped to 21-35 on the road this season, better than only five major league teams. The Nationals will play nine more games in their final three-city swing of the season, nine chances to either change or affirm a troubling trend that has helped prevent them from climbing out of last place.

When the Nationals have played at home for the past two years, they are a respectable, even formidable team. They finished over .500 at Nationals Park last year, and this year they are 32-23 at home. On the road, they’re a mess. Last year, they finished 28-53 away from home. So, since the start of last season, the Nationals are 73-63 at home, 49-88 on the road. Home field creates an advantage for most every team. For the Nationals, it has created, virtually, two divergent teams.

“Anytime you have a worse record, you think you can do better,” third baseman Ryan Zimmerman said. “There’s really no reason or anything. You can’t put your finger on any reason why we play better at home. But it’s one of those things we’re going to have to get better at.”

The Nationals had a chance, at least Thursday night, to reverse that trend. They stayed in the game until the eighth, when Ryan Mattheus, whom the Rockies drafted in 2003 and traded to the Nationals in 2009, allowed three runs in his first career appearance at Coors Field.

The Nationals’ offense could not convert scoring chances early and sprung to life only after the Rockies had sealed the game against Mattheus. In the first six innings, the Nationals stranded nine runners, five of them in scoring position. Zimmerman drilled a two-run double in the ninth, at which point the Nationals trailed by five.

Making his second start of the season, and first since Manager Davey Johnson removed him from a long-relief role, Detwiler allowed two runs in five innings, giving up five hits and walking three. Detwiler recorded his lone strikeout on an impressive, 94-mph high fastball he blew past Chris Nelson to end the second.

Detwiler did not allow a hit until the fourth, when after a one-out walk he yielded three consecutive singles. The second, by Ty Wigginton, scored the Rockies’ first run. The third, by Nelson, rolled slowly into right field.

As Jayson Werth charged the ball, Troy Tulowitzki steamed around third base. Werth buzzed a throw all the way to the plate, ankle-high when Wilson Ramos caught it. Ramos rooted his left leg in the dirt and repelled Tulowitzki’s slide, tagging him out. Rather than being down a run and stuck in a jam, the Nationals were still tied and Detwiler could operate with two outs. The inning ended with a lineout one batter later.

Detwiler relinquished the lead in the fifth, after Chris Iannetta led off with a double to left-center field. After a sacrifice bunt, Eric Young Jr. ripped a single to center that scored Iannetta and gave the Rockies the lead for good. Detwiler got out of the inning with two flyballs, but after his smooth start, six of the final 11 batters Detwiler faced reached base.

Detwiler still pitched well enough for the Nationals to win, but after Michael Morse’s RBI single in the first inning scored Rick Ankiel, the Nationals could not deliver a clutch hit against Colorado starter Esmil Rogers.

“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. We just couldn’t capitalize on them.”

In four of the first six innings, the Nationals ended an inning by striking out with a runner in scoring position, two of them by Laynce Nix and two by Ankiel. The Nationals’ last best chance to get back in the game came in the sixth, which they entered trailing by a run. Ian Desmond walked with one out. Alex Cora, pinch-hitting for Detwiler, roped a two-out double into the corner that put runners on the corners and knocked Rogers out of the game.

Rockies Manager Jim Tracy summoned left-handed reliever Matt Reynolds to face Ankiel, perhaps the Nationals’ hottest hitter. Ankiel saw four pitches, the last a slider in the dirt he flailed at for strike three.

In the bottom of the inning, Tulowitzki crushed a home run against Collin Balester. The Nationals would not give themselves another chance to get into the game. Colorado closer Huston Street finished the Nationals off in the ninth when Morse flied to right. The Nationals collected their things in the dugout and retreated to the visitor’s clubhouse, the end of another long night on the road.

“Good ballclubs win on the road. And I think we can be a good ballclub,” Johnson said.