LOS ANGELES – Standing at the top step of the Diamondbacks’ dugout on Saturday afternoon, right-hander Mike Bolsinger did not look like a man a couple of hours away from making his first major league start.

Betraying no emotion, he stretched casually. He posed for pictures with his family. He nonchalantly took General Manager Kevin Towers’ cell phone and received well wishes from another member of the Diamondbacks’ front office.

Then, once the game started, he looked just as unflappable on the mound — at least until the fourth inning started.

Bolsinger cut through the Los Angeles Dodgers’ lineup for three innings on Saturday before falling apart in the fourth and fifth innings of an 8-6 loss at Dodger Stadium.

Looking to build on Friday night’s hard-fought extra-inning victory, the Diamondbacks instead stumbled, letting a 4-0 lead slip away and losing for the seventh time in eight games.

In dropping to 5-15, they remain one of the more talked about teams in the game. This week, a rival executive called them “the most interesting team in baseball,” in large part because no one expected them to be this bad.

Count Dodgers right-hander Dan Haren among them. Haren, who beat the Diamondbacks for the second time this week, thinks his former team is better than the record indicates.

“I’m pretty sure they’re going to turn it around,” he said. “I think the rotation has struggled up to this point — pitching can be just as contagious as hitting. You get a couple bad starts in a row and guys get in a funk. I’ve seen it before.

“The lineup from top to bottom is too good. They’re going to score enough runs and the pitching is going to better.”

Yet somehow it keeps managing to get worse. After Wade Miley gave the D-backs a strong start on Friday night, Bolsinger coughed up seven runs (six earned) in four-plus innings. The Arizona rotation ERA was at 7.26 entering the day and at 7.50 at the end of it.

Helped along by an error on Dodgers shortstop Hanley Ramirez, the D-backs jumped on Haren in the third inning. Paul Goldschmidt lined a two-run single to right and Miguel Montero laced an RBI double, and Arizona had a 4-0 lead.

Meanwhile, the little-known Bolsinger, who has pitched well at every minor league level but who has never earned much acclaim from scouts, was cruising, retiring nine of the first 11 batters he faced.

But with one out in the fourth, Adrian Gonzalez and Matt Kemp shot singles to center, and Andre Ethier followed by drilling a fastball out to right field for a three-run home run.

“I just left it up,” Bolsinger said. “I was doing pretty well the whole game of locating the fastball in and out, and I just kind of left one up.”

The mistakes multiplied in the fifth. Haren, Dee Gordon and Carl Crawford started the inning with consecutive singles to load the bases. Then Ramirez hit what looked like a double play ball to third base, but Martin Prado couldn’t make the play, a run scoring on the error.

That was the end of Bolsinger’s night, but Gonzalez (two-run single) and Kemp (two-run double) greeted reliever Oliver Perez with hits, blowing the game open.

“I left some balls up and when you do that up here, there’s consequences,” Bolsinger said. “It’s how you respond to it. Each time I’ve been out there, I’ve kind of learned. I learned a lot from my first time out (a relief appearance) and I kind of learned a lot from this start. Hopefully, I can take it on to the next one.”

Arizona scored four times off Haren in the third inning and seemed on the verge of breaking the game open, but Haren settled down and pitched into the eighth inning. He gave up five runs (two earned) in 7ª innings.

“He just keeps the ball down, he throws a lot of strikes, it’s tough,” Goldschmidt said. “He did a good job. Really, we had some good at-bats the whole game but just not good enough.”