The Washington Nationals erased most of a seven-run deficit Saturday night and still had three innings remaining.

But their hopes of a comeback ultimately dissolved into a lopsided 15-7 loss to the Colorado Rockies, a defeat accompanied by some statistical humiliation.

The 15 runs were the most allowed by the Nationals this season and largely the result of a poor start by Livan Hernandez and shaky outings in the seventh by Todd Coffey and eighth by Henry Rodriguez, when the Rockies combined for their final five runs, all with two outs.

Hernandez (6-11) lasted 3 2-3 innings, his shortest start since he also went that distance on Sept. 22, 2009, against the Los Angeles Dodgers. He gave up nine runs, matching his career-high. It's the fourth time Hernandez has yielded nine runs and second at Coors Field.

"It a tough ballpark, a tough ballclub for him," manager Davey Johnson said. "He wasn't real sharp, and when he's not on, bad things happen."

Hernandez cited two mistakes he made that led to the Rockies four-run third. After giving up a leadoff single to Chris Iannetta, who had four of the Rockies' 19 hits, pitcher Jhoulys Chacin tried to bunt and Hernandez hit him with a pitch. Hernandez then fielded Eric Young Jr.'s sacrifice attempt on the third-base side of the mound, threw off the wrong foot and the ball sailed wide of first base.

"I never make errors like that," Hernandez said. "I got a chance to make (an) out at second base and I no throw it. I freeze, and I throw the ball and I short-arm it. You know, I never do that."

One run scored on the play, and Young ended up at third. Dexter Fowler, who tied his career-high with four RBI, lined a two-run triple into the right-field corner and scored on Troy Tulowitzki's sacrifice fly.

The Nationals are 7-17 in games started by Hernandez, and Johnson said he might be replaced in the rotation when the rosters are expanded next month.

"He's pitched a lot of good games," Johnson said, "but unfortunately when he's a little off, he's really off."

The Nationals, who finished with 14 hits, quickly got two runs back in the fourth against Chacin (9-8), who lasted five innings and snapped a four-game losing streak that spanned eight starts since his last win June 15.

Chacin gave up a run-scoring double to Michael Morse, who tied his career high with four hits, drove in three runs and raised his average to .327. Chacin issued three of his five walks in the inning and allowed a second run to score on a wild pitch with the bases loaded. But he then struck out Wilson Ramos and retired Hernandez on a groundout.

The Rockies struck for five runs in the fourth and finished Hernandez, whose reliance on breaking pitches and slow stuff makes him a bad match for spacious Coors Field, where he pitched the final two months of the 2008 season for the Rockies. In 19 career starts at Coors Field, Hernandez is 4-8 with a 7.33 ERA and has allowed 148 hits in 108 innings.

Hernandez gave up a leadoff homer in what became a five-run fourth to Ty Wigginton and a one-out homer to Iannetta.

"You make a mistake in this park and you're going to pay for it," Hernandez said. "The first one was supposed to be outside and it run in and the guy hit it out. That other one, the curveball's supposed to be outside and it go the other way. It's difficult to control the ball here."

After Iannetta's homer, Hernandez gave up four singles to the final five batters he faced. Hernandez's wild pitch brought home the third run of the inning and the final two scored on singles by Carlos Gonzalez and Tulowitzki.

The Nationals erupted for four runs with two out in the sixth against Greg Reynolds. He was scratched from his start Friday at Triple-A Colorado Springs after Juan Nicasio was struck in the head with a line drive.

Reynolds began his fourth tour with the Rockies this season by giving up five straight two-out hits. Rick Ankiel hit a two-run homer, and the barrage continued with doubles by Danny Espinosa and Ryan Zimmerman, who extended his hitting streak to 15 straight games, and a single by Morse.

"I feel good about the offense," Johnson said. "The pitching needs to be straightened out a little bit."

Tom Gorzelanny allowed one run in 2 1-3 innings in relief of Hernandez. But Coffey gave up three straight hits and three runs in the seventh. Young singled home the first run, and Fowler doubled home the final two.

Johnson turned to Rodriguez in the eighth. He pitched Friday night, didn't retire any of the four batters he faced and gave up three hits, one walk and one run. Rodriguez pitched a full inning this time but allowed two hits and two runs and threw a wild pitch.

"A lot of times when a guy has a rough outing, I want to get him out there quick," Johnson said. "Henry's throwing strikes. He's still learning how good he can be."

NOTES: During his 15-game hitting streak, Zimmerman is batting .444 (28 for 63) with seven doubles and seven RBIs. Five of the seven RBIs have come in his past two games. ... Morse matched his career-high for a single game with four hits, the third time he has done. He has gone 18 for 35 (.514) while hitting safely in eight straight games, seven of them multi-hit games ... Espinosa had two doubles, the first multidouble game of his career.