PITTSBURGH -- The Pirates were built on the idea that their pitching staff would keep them in every game they play this season. They believed the back end of their bullpen would be a strength and their rotation was strong enough, one through five, to give them a chance every time they took the field.

That hasn’t been the case lately. Pittsburgh’s starting staff kept the club afloat as the lineup scuffled through the first month of the season. But too often this month, the Pirates’ pitching hasn’t put them in a position to win, and that was the case again Sunday afternoon. Chris Archer gave up four runs and walked six batters in five innings as he lost his fifth straight start, and the Pirates fell to the Dodgers, 11-7**,** at PNC Park.

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“It’s been four starts that I haven’t pitched to my capability whatsoever,” Archer said. “My next one could be a great one, and it will be a great one. It will be better than today.”

The Pirates could use Archer at his best atop their rotation.

At the end of April, Pittsburgh’s rotation owned a 3.15 ERA, the second best mark in the Majors. In 23 games this month, the Pirates’ starters (and openers) have combined to record a 6.71 ERA that ranks among the worst in baseball.

The good news, relatively speaking, is that the Pirates won’t have to see the Dodgers again this season. Los Angeles swept the season series, 6-0, and outscored the Bucs, 44-20, in those six games.

“I’ve faced a lot of good lineups, and I’ve learned that anybody with a stick in their hands is dangerous,” Archer said. “They’re especially dangerous.”

Yes, they have dealt with injuries. Few teams can withstand the loss of their top two starters from Opening Day, and the Pirates are still without both Jameson Taillon and Trevor Williams. But the Pirates also expressed confidence in their depth during Spring Training -- the depth of their rotation and the next men up -- and that depth has been repeatedly challenged.

Further complicating matters has been the performance of Archer. The Pirates were counting on the veteran right-hander to be a steady presence in their rotation, but he has not put together a quality start since April 13. On Sunday, he needed 105 pitches to get through five innings.

“I think he’s working hard to get outs, and his fastball command has been just off enough that it’s extended counts,” Pirates manager Clint Hurdle said. “When you’re talking about dealing over 100 pitches in five innings, roll your sleeves up -- that’s a lot of work. That’s been the challenge. I just think it’s nailing down the delivery consistently.”

Archer held the Dodgers to one run in his first four innings Sunday, only to give up a one-run lead in the fifth. He walked leadoff man Max Muncy, gave up a single to Justin Turner, walked Cody Bellinger and then surrendered a two-run single to Matt Beaty. Bellinger scored on a groundout to put the Dodgers ahead by two runs.

“Poor fastball command. At times it was there; at times it wasn’t,” Archer said. “It’s way too many free passes. Playing with fire the whole game, then finally it all caught up to me in the fifth inning.”

Adam Frazier homered off Dodgers starter Kenta Maeda to pull the Pirates within a run, then Hurdle sent rookie Montana DuRapau to the mound to pitch the sixth rather than calling upon Francisco Liriano against a stack of left-handed hitters. DuRapau recorded one out and was charged with six runs, including three earned runs and two that scored with Dovydas Neverauskas on the mound.

“If we would have tied the game, we would have gone to Liriano. It’s hard to pitch your front edge [Liriano] to get to the back end [Kyle Crick and Felipe Vazquez] in the sixth inning when you’re losing,” Hurdle said. “That was my thought. It didn’t work out.”

There is no rest coming for the Pirates’ bullpen, either. The Bucs will play at least 18 innings Monday as they begin a four-game, three-day series against the Reds in Cincinnati. Their pitching plan for the upcoming series reveals how their unpredictable, injury-filled season has veered from the plan they had in mind.

On Monday night, top prospect Mitch Keller will make his earlier-than-expected Major League debut. The other three games will be started by pitchers who competed for the fifth spot in their rotation this spring: Nick Kingham (Game 1 on Monday), Jordan Lyles (Tuesday) and Steven Brault (Wednesday).

There likely isn’t help on the horizon, at least not from outside the organization.

“Three percent of trades over the last decade happened in April and May. It’s a really small number,” general manager Neal Huntington said. “Those few teams that might be willing to trade you a mediocre starting pitcher are going to ask for a king’s ransom. Every pitcher that’s become available, we’ve talked about. … That’s the challenge here. We continue to challenge our internal numbers, but continue to look externally as well.”

While Lyles has been the Pirates’ most consistent starter, Kingham and Brault have moved from the Opening Day bullpen to the rotation to a quasi-starter role as “bulk” pitchers (following an opener) and now, back to the rotation.

“We’ve had some young pitchers who haven’t stepped up at the Major League level, and it’s time,” Huntington said. “It’s time for some guys to come out here and take strangleholds on jobs. Otherwise, we’ll move on.”