Colorado's four-man rotation with a 75-pitch limit is here to stay, manager Jim Tracy said before the game.

He thinks it's too soon to make any judgments — even on nights that look as bad as Tuesday.

"It's not a 10 or 12-game sample where you formulate an opinion on it one way or the other," Tracy said of the plan installed on June 19 in Philadelphia. "I think you allow it to evolve first and see how it goes."

It went horribly in a 12-5 loss to the Washington Nationals, Colorado's 15th loss in 19 games.

"Tonight was a night quite frankly where it blew up," Tracy said.

Adam LaRoche homered twice, and Ryan Zimmerman collected his 1,000th career hit and also homered for Washington.

Ian Desmond went 4 for 4, Michael Morse had four hits and Tyler Moore also connected for the Nationals, who had a season-high 21 hits, which tied the club mark since the team moved to Washington in 2005.

They had 11 extra-base hits, the most since becoming the Nationals.

Starter Christian Friedrich (4-5) left the game trailing 4-3 after getting Bryce Harper out with his 70th pitch to start the fifth inning. Reliever Guillermo Moscoso imploded, needing half that many pitches to get the final two outs in the fifth.

"Guillermo didn't have anything and his numbers indicated that," Tracy said. "That was the time the game got away."

Moscoso gave up two singles and a four-pitch walk to LaRoche. Desmond drove in two, with a two-strike double off the left-field wall, and Moore hit a three-run homer before Moscoso escaped a 35-pitch inning.

Washington wasn't through with Moscoso, adding three more in the sixth. He finished his night with 63 pitches, yielding eight runs and eight hits in 1 2-3 innings.

"I had been throwing the ball well in games and I get in the game and I couldn't make good pitches," Moscoso said. "I couldn't get my pitches in the right spot."

Dexter Fowler and Jonathan Herrera homered and Jordan Pacheco had three hits for the Rockies.

Gio Gonzalez (10-3) picked up the win despite allowing five runs, four earned, on eight hits in six innings. He struck out seven.

Zimmerman entered the game with 998 career hits and reached the 1,000 mark in his third at-bat, a single to right in the fifth inning. He added his fourth home run of the season in the sixth to finish with three hits.

LaRoche put Washington up 1-0 in the second with his 14th home run of the season. Morse's two-run double in the third made it 3-0.

Colorado tied it in its half of the inning on Carlos Gonzalez's RBI double and run-scoring singles from Michael Cuddyer and Todd Helton. Cuddyer scored on Harper's throwing error to make it 3-all.

Gio Gonzalez made it 4-3 with a two-out RBI single in the fourth. The inning was kept alive by a double by Jesus Flores.

"Flores was the batter I would like to have back," said Friedrich, who allowed four runs on nine hits and struck out three in 4 1-3 innings. "I had him 0-2 and when it was 1-2, I threw a slider that I left up."

NOTES: The Rockies announced that LHP Edwar Cabrera would be called up from Double-A Wednesday to start for Colorado. ... Before the game, Rockies pitching coach Bob Apodaca asked to be reassigned and he was made a special assistant to GM Dan O'Dowd. Bullpen coach Jim Wright and Triple-A pitching coach Bo McLaughlin will serve as co-pitching coaches for the remainder of the season. ... LaRoche now has 17 career multihomer games. ... The Nationals will send RHP Jordan Zimmermann (3-6) to the mound Wednesday.