Strasburg (9-2) was trying to become the first Nationals pitcher ever to win seven consecutive starts, and it looked early like he'd accomplish that.
In his first five innings, Strasburg struck out seven and gave up just one run on three hits in his Coors Field debut. The high altitude that has so often bothered visiting pitchers didn't have the same effect on Strasburg, who played many away games in Colorado and Utah while in college at San Diego State.
"It's a little different, your pitches won't move like they normally do so you have to focus on commanding it," Strasburg said. "When you try to put a little more break on it, it hangs a bit. I was lucky to pitch at an elevation in college and be accustomed to how it comes out of your hand."
Strasburg was even an offensive force out of the No. 9 hole, advancing Jesus Flores to second on a sacrifice bunt in the third -- Flores would score the game's first run -- and doubling in the go-ahead run in the fifth.
But Strasburg gave up his third triple of the season to Rockies leadoff hitter Dexter Fowler to begin the sixth and unintentionally pegged Marco Scutaro in the helmet to put runners on the corners with nobody out. Scutaro is listed as day-to-day by the Rockies.
"I was trying to throw a sinker and it got away from me," Strasburg said. "It happens, part of baseball. You try to get in and obviously you never want to hit a guy in the head, but you have to keep going out there and pounding the strike zone. You think about it for a second, and hope he's OK."
Said Nationals manager Davey Johnson, "We've all been hit. I don't blame [Strasburg], he certainly wasn't trying to hit [Scutaro] there. I don't want to make anything more of it than it is."
Bad fortune quickly turned worse for Strasburg. A 2-2 pitch to Carlos Gonzalez, who had struck out twice earlier, was called a ball -- Strasburg himself thought it could have gone the other way -- to set up a 3-2 count.
Strasburg hung a curveball over the plate -- "A bad pitch selection," said Johnson -- that Gonzalez drove to center to score Fowler with the tying run. Michael Cuddyer followed with a single to right to move Chris Nelson, pinch-running for Scutaro, to third.
Todd Helton then lunged for a low changeup and got enough of the ball to float it to center field for a sacrifice fly that made the score 3-2.
"Carlos had a great at-bat, Cuddy had a great at-bat and it gave me the luxury of hitting a pop fly to get a runner in," Helton said. "I didn't hit it well. It was a terrible swing. It was a good pitch, down but in that situation I'm protecting, just trying to get a run in."
The inning wound up chasing Strasburg from the game. His final line after six innings of work: Six hits, three earned runs and eight strikeouts on 97 pitches. It would have been enough to earn the win on most nights, but not for the Nationals on Monday.
Rockies starter Jeff Francis wasn't in a position to get his first win, but the southpaw did his part to contain an offense that entered the day with the third-fewest runs and hits in the National League. Francis scattered five hits to go with five strikeouts -- two against Bryce Harper.
"I felt like I was in control," Francis said.
After the game, Johnson was upset at his club's plate discipline. Several times, the Nationals swung and missed on pitches out of the zone and never seemed to capitalize on Francis' lack of fastball speed -- 84 miles per hour -- or what Johnson called a "slow hook."
"Our approach is not great, as far as I'm concerned," Johnson said. "We're getting caught in between fastballs and breaking balls, chasing out of the zone. It's got to improve. We've got too much talent to not be swinging the bat well."
The Nationals, who own the third-lowest batting average in the National League, did manage one more hit than the Rockies, but most were scattered. Ian Desmond tripled off Josh Roenicke -- his brother-in-law -- with two outs in the sixth, but Washington couldn't bring him in.
Roenicke (3-0) pitched the Rockies through the sixth and seventh innings, yielding just the one hit.
The Nationals had a chance in the ninth inning, with runners on first and second and one out against Rockies closer Rafael Betancourt.
But Roger Bernadina hit a sharp line drive right to Cuddyer in right field and Danny Espinosa grounded out to second to end the threat and give Washington its seventh loss in 10 games.
Despite the recent swoon, the Nationals still lead the National League East by 3 1/2 games, with a weekend series against second-place Atlanta looming. But they know they have to take care of business against the Rockies first.
"We've just got to get something going here," Johnson said.