DENVER — In the 10th consecutive winless start for Shelby Miller, the Braves’ All-Star finally showed some frustration.

Miller, who allowed a career-high 11 hits in five innings, tossed his glove and hat into the dugout as he came off the field following a three-run fourth inning, when the Rockies opened a four-run lead en route to a 5-3 win at Coors Field.

“He got a little frustrated — I think more frustrated with himself,” said manager Fredi Gonzalez, whose Braves have lost three in a row since their 6-1 start in July. “He was fighting his delivery a little bit on some of his pitches, left some balls over the plate a little too much.”

Rather remarkably, it was the Braves’ eighth loss in the past nine starts by Miller (5-5), who has a career-high four-start losing streak despite entering Friday with the National League’s third-best ERA (2.07). His ERA climbed to 2.38 after Miller was charged with a season-high five earned runs in five innings, with one walk and seven strikeouts.

“It’s just the worst my fastball command’s been all year, it’s not even close,” said Miller, who is 0-4 with a 3.32 ERA in his past 10 starts, after going 5-1 with a 1.33 ERA in his first eight. “I probably threw more balls than I did strikes with my fastball tonight. I just didn’t get ahead in the count, left balls over the middle of the plate, everything was up, and it was just a terrible day.”

The Braves have scored one or no runs while he’s been in seven of his past 10 starts. That included no runs while he was in any of his past four starts before Friday, when they didn’t score until Kelly Johnson’s three-run homer in the sixth inning cut the Rockies’ lead to 5-3.

While the Braves totaled a respectable 18 hits combined in the first two games of the four-game series, they scored in only one inning each night and lost 5-3 both nights against a team that had lost nine of 11 before this series.

“Their offense…they’ve obviously got some players,” said Johnson, whose nine home runs rank second among Braves behind injured Freddie Freeman (12), while Nolan Arenado leads the Rockies with 24. “I mean, they’re doing well, unfortunately for us. We are getting close, though. It’d be nice if we could get a few more runs in this place.”

The Braves have lost four in a row against the Rockies, all at Coors Field. They’ll need to win the last two games before the All-Star break to salvage a split of this series and avoid a losing record on a seven-game road trip that started with a 2-1 series win at Milwaukee.

They liked their chances before Friday’s game, since the Braves had their best pitcher going against Rockies journeyman reliever Gonzalez Germen, called up from Triple-A on Friday to make his first major league start as an emergency fill-in. All he did was limit the Braves to one hit and one walk in three scoreless innings.

Miller has steadfastly defended teammates while being undermined by poor run support during his winless streak, always blaming only himself, even when it was obvious that he’d pitched well enough to win. On Friday, he did it again, saying his fastball command was the worst it’s been all season and that he never felt like he had anything going.

Miller gave up a run in the first inning on consecutive hits on a single and Arenado’s one-out double. He worked around hits in the second and third innings without damage, but got into trouble immediately in the fourth after a leadoff single by Nick Hundley. Daniel Descalso followed with a RBI triple and Brandon Barnes singled to push the lead to 3-0.

One out later, things got ugly.

Left fielder Jonny Gomes couldn’t catch up to Charlie Blackmon’s triple that landed just in front of him as he dove near the warning track, and center fielder Cameron Maybin was shaded toward right and couldn’t sprint far enough to reach DJ LeMahieu’s fly ball left of straighaway center until it was too late. The ball landed beyond his outstretched glove and bounced off the warning track and over the fence for a ground-rule double that scored Blackmon for a 4-0 lead.

“I didn’t have anything sharp,” Miller said. “Nothing was very good tonight at all.”

Miller has allowed one run and six hits in 15 innings of two home starts (in St. Louis) against the Rockies, but he’s been rocked for 17 hits and eight runs in 7 2/3 innings of two starts at Coors Field.

“Yeah, it’s a tough place to pitch,” he said. “It’s a big outfield, having to run some balls down in the gaps, they’re, like, 390 (feet), 415 to center. It’s hard to cover that outfield, it’s a big outfield. We’ve got guys tracking down balls, trying to make plays, it’s just falling in there. Which is expected here, for sure.”

Pitching coach Roger McDowell came out to chat with Miller, who spiked the rosin bag near the mound. Miller threw a pitch high and inside to the next batter, Arenado, who was not pleased by the proximity of the pitch to his head.

Arenado grounded out to end the inning, and as Miller came off the field, he tossed first his glove and then his hat into the dugout before he got to the steps.

After Miller left, Gonzalez made a surprising move to bring in Manny Banuelos to start the sixth inning. Surprising in that Gonzalez had said Banuelos would be available in the bullpen Saturday or Sunday, but didn’t mention Friday as a possibility, since the rookie left-hander had thrown 92 pitches in a start Monday at Milwaukee.

But he threw just one inning Friday, using that in place of what normally would’ve been his between-starts side session in the bullpen.

Banuelos had originally been scheduled to start the series finale Sunday against the Rockies, but Alex Wood was moved to that slot after Wood threw just two pitches in the first inning before a rain delay of more than two hours, after which both managers pulled their starters.

Germen was called up from Triple-A to make an emergency start in place of David Hale, who’d been scheduled to start Friday but took over in the second inning Thursday after a rain delay of more than two hours forced both teams’ starters out of the game. (Hale would leave with a strained groin.)

Germen, a 27-year-old right-hander, not pitched in the majors since May 4, before he was released by the Cubs after posting a 7.50 ERA in six relief appearances. He has a 4.58 ERA in 60 relief appearances over three seasons with the Mets and Cubs, and last worked as a starter in 2012 in the minor leagues.