Washington (AP) -- Bryce Harper was a very visible presence at Nationals Park early Sunday.
He took batting practice on the field for the first time since going on the disabled list June 1, and the first 15,000 fans received Harper bobblehead dolls.
But he wasn't in the lineup on yet another day when his bat could have made a difference.
Colorado's Michael Cuddyer homered in his first at-bat to extend the major league's longest hitting streak this season to 21 games, and Ross Detwiler gave up seven runs in just 3 2-3 innings, and a Washington comeback fell short in a 7-6 loss.
Washington dropped its second straight and fell to 37-38, six games behind Atlanta, which won at Milwaukee. The Nationals trailed 7-0 in the fourth, but pulled to 7-6 with a four-run eighth.
"It was a good effort coming back a little and scoring some runs late which, we've been doing a lot more lately," Washington third baseman Ryan Zimmerman said. "A step in the right direction."
Zimmerman had an RBI infield single in the eighth inning, and a second run scored on the play when Rockies short stop Josh Rutledge booted the ball. Jhonatan Solano pinch hit and lined a two-out, two-run double to centerfield.
But Ian Desmond struck out, and the Nationals' failed to score in the ninth.
"Lately we've played two or three good games in a row and then gone right back to where we were," Zimmerman said. "Long way to go still, just got to keep taking the positives like today and go with that."
In his shortest start this year aside from a May outing he left early due to lower-back spasms, Ross Detwiler (2-6) allowed a season-high seven earned runs -- three more than any other game.
"Basically he's a sinkerball pitcher. He's still very young, learning how to use all the weapons in his arsenal," Johnson said of Detwiler. "Today he didn't feel like he had a good sinker so he threw more changeups. It's sequence pitching. He's been relying since he's been here basically on his fastball.
"It's a good hitting fastball club and if you don't hit your spots -- sinkers down and away -- they're going to hurt you," Johnson added.
Detwiler's explanation was more succinct.
"They didn't hit the ball that hard today," Detwiler said. "There was two hard hit balls, and everything else just fell in."
In eight starts before going on the disabled list with a strained right oblique, Detwiler fashioned a 2.76 ERA with 23 strikeouts and 10 walks in 45 2-3 innings. In his last three starts, the left hander has allowed 14 runs in 14 2-3 innings and his ERA has risen to 4.18.
The Nationals managed 13 hits and five walks off Rockies pitchers, but went just 3 for 14 with runners in scoring position and left 11 men on base.
Harper, who hasn't played since May 26 due to left knee bursitis, is scheduled to begin a rehabilitation assignment this week. The 20-year-old outfielder put a batting practice power display for those who arrived early to get a Harper bobblehead, but then his day was over.
Washington right fielder Jayson Werth started after missing Saturday's game with flu-like symptoms, but left in the fourth inning following his second hit.
Johnson said Werth was examined by the team's medical staff and diagnosed with a left groin pull. It's uncertain whether Werth, who recently returned from a right hamstring injury, will need to go on the disabled list.
"Know more tomorrow," Werth said "I think I'll be all right. Groins are pretty straight forward. I've had a couple of them in the past, but never missed any time so I'm hoping that will be the case."
Cuddyer, who also extended his Colorado record for consecutive games reaching base to 40, had an RBI single in Colorado's three-run third inning and a two-run single in a three-run fourth, an inning Nolan Arenado led off with a home run.
That gave Jorge De La Rosa (8-4) a 7-0 cushion. He allowed seven hits in six innings, trading both his earned runs for outs in the bottom of the fourth.
NOTES: Johnson said RHP Dan Haren is headed to the disabled list. Haren, who yielded six earned runs in 3 1-3 innings Saturday to drop to 4-9 with a 6.15 ERA, said his shoulder has been bothering him his last few starts. "Nothing really major," Haren said. "Nothing I haven't pitched through in the past. I'm not concerned about it, but they wanted me to take some time to get 100 percent." He said he'll probably have an MRI this week. ... Nationals LHP Gio Gonzalez (3-3, 3.34) will face Arizona Diamondbacks RHP Trevor Cahill (3-8, 3.92) on Tuesday.
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