Hanley Ramirez homered for the Dodgers, who have lost three straight after winning their first game following a nine-player deal that brought Adrian Gonzalez and Josh Beckett to Los Angeles.
That might be the least of their worries.
The Dodgers lost Matt Kemp to a right knee contusion after he crashed hard into the wall in center field trying to chase down Josh Rutledge's triple in the first inning.
He left the ballpark to have precautionary X-rays and a CAT scan on his jaw and an MRI on his knee, the Dodgers said. The team said he had no concussion symptoms.
''That kind of hit I'm expecting him to at least be out tomorrow,'' manager Don Mattingly said. ''I'm sure he'll tell me can play if he walks back in here tomorrow, but I'm expecting him to be out tomorrow.
''The biggest bright spot, if you can take a bright spot, the knee didn't look damaged. We'll see what's going on with the jaw. If it was wired shut it would kill his mojo.''
It would be a blow to a team that has struggled against two last-place clubs. After a loss to Miami on Sunday the Dodgers have dropped two straight to Colorado, which has 27 hits in the series.
They trail San Francisco by four games in the NL West after the Giants beat Houston on Tuesday.
''It's more frustrating against the team we're playing,'' right fielder Andre Ethier said. ''It starts with each one of us looking ourselves in the mirror and saying we need to go out there and play better.''
Andrew Brown had three hits for the Rockies, who have won eight of 10.
Monday's game got away from the Dodgers late. On Tuesday, the Rockies jumped on them early.
Rutledge started the first-inning rally with a deep drive to center that put Kemp out of the game. The ball bounced off the wall just before Kemp turned into the padding while running full speed and fell backward onto the warning track.
He stayed down for several minutes as team trainers checked him over. He got up, took a drink of water and initially stayed in the game.
''He was talking fine. He was actually kind of funny,'' Mattingly said. ''He was like, `I'm not coming out of this game, I'm not coming out of this game.'''
He stayed in, but not for long.
The next batter, Jordan Pacheco, looped a double that Kemp laid out for but didn't catch. Rosario followed with a single to center to score Pacheco, and Kemp left after fielding the ball.
''It was an in-between ball and we both had a good jump at it,'' Ethier said of Pacheco's double. ''I saw him coming and I peeled off at the last second. Hopefully it's just a thing where a little rest tonight and he'll be back tomorrow.''
The Rockies scored two more runs off Chris Capuano in the first on a single by Brown and a double by DJ LeMahieu to make it 4-0.
The Dodgers got a run back on a sacrifice fly by A.J. Ellis in the second inning.
Rosario made it 5-1 with his 22nd homer in the third.
''The at-bats that Wilin Rosario took tonight were very special,'' Rockies manager Jim Tracy said. ''He hits his 22nd home run, but he drives in a couple of runs. He hits a breaking ball for a home run — that tickled me to death.''
Capuano (11-10) allowed six runs on 10 hits and struck out three in six innings. It was the second consecutive game he has allowed six earned runs.
The Dodgers loaded the bases with no outs in the fourth but scored just one run on Adam Kennedy's double-play grounder to LeMahieu at second.
LeMahieu was busy, recording 12 assists to tie the major league record for most by a second baseman in a nine-inning game.
Harold Reynolds was the last one to accomplish the feat, on Aug. 27, 1986, the Rockies said.
''When can you recall him mishandling a ball? I think the only time I remember was a play in during our series in Chicago,'' Tracy said of LeMahieu. ''He has a field awareness.''
Colorado padded the lead with a run in the bottom of the fourth and two more in the seventh off reliever Jamey Wright.
Chatwood (4-3) battled through five innings to get the win. He allowed two earned runs, walked three and struck out four.
Ramirez led off the ninth with his 21st homer of the season to make it 8-4.
NOTES: Rosario is three home runs shy of Todd Helton's club record for homers by a rookie. ... Rockies OF Carlos Gonzalez was given the night off. ... Dodgers RHP Matt Guerrier could be activated from the 60-day DL when the rosters expand Saturday. Guerrier has missed 117 games since being placed on the DL with tendinitis in his right elbow. ... Rockies SS Troy Tulowitzki (groin surgery) will go on a rehab assignment to Triple-A Colorado Springs starting Wednesday.