PHILADELPHIA — For the better part of almost two months, the Dodgers have been a .500 team.

And the biggest problem in that time — a lack of reliable starting pitching from an injury-plagued, rookie-reliant rotation — only seems to get worse with each passing day.

In the offseason, the Dodgers thought they had fixed their recent starting pitching woes. They traded for Tyler Glasnow. They signed Yoshinobu Yamamoto. They spent nearly half a billion dollars trying to bolster both the top of their rotation, and the depth options behind it.

This week, however, in a series sweep against the Philadelphia Phillies that was cemented with a 5-1 loss Thursday, it’s clear the club’s rotation is an area of concern again.

And not with any easy, obvious fixes.

“If you had told us in spring training that we would be where we’re at with the depth of our starting pitching, I would have doubted it,” manager Dave Roberts sighed before Thursday’s game. “But, we are.”

Indeed, the Dodgers pitching staff is facing question marks almost everywhere it looks.

This week, in what was supposed to be a marquee matchup between the National League’s top two teams, the Dodgers instead struggled to piece together production on the mound.

The problem was made all the more magnified by a slumping lineup that scored just five runs in three games at Citizens Bank Park, and an error-prone defense that contributed to several Phillies’ rallies, including a decisive two-run sixth inning Thursday that started on a fly ball James Outman couldn’t get to in center field.

“They’re clearly a better team than we are right now,” Roberts said.

Added first baseman Freddie Freeman: “We didn’t play very good that series. There’s nothing to spin it any different way.”

In the long term, though, it’s the pitching issues that look toughest to solve.

Philadelphia’s Trea Turner rounds the bases after hitting a home run off Dodgers pitcher Anthony Banda during the first inning Thursday.

(Matt Slocum / Associated Press)

The team was unable to call on Glasnow, its lone All-Star arm, after he joined Yamamoto on the injured list Tuesday.

They decided they could no longer count on second-year right-hander Bobby Miller, demoting him to triple A on Wednesday after a nine-run clunker in the series opener.

And while rookies Gavin Stone and Landon Knack — who gave up three runs in 4⅓ innings of bulk relief Thursday, the best outing by a Dodgers pitcher this week — were solid against the Phillies’ high-scoring lineup, neither were close to spectacular either, a stark reminder of the team’s sudden lack of an established ace amid all the other key absences it’s facing.

“I try not to fret too much or worry too much about the guys who can’t help us right now,” Roberts said, referencing a group that includes Clayton Kershaw, Walker Buehler, Dustin May and several other injured arms. “[We’re] hoping that they’ll be back soon.”

Glasnow is expected to return shortly after next week’s All-Star Game.

Beyond him, however, the other injured pitchers in the organization offer little assurance of front-line success.

Yamamoto still hasn’t restarted catch play, suggesting that he remains a month or more from a comeback.

Buehler is working at a private facility in Florida, trying to find any semblance of consistency after eight rough starts in his return from Tommy John surgery.

Kershaw will resume his minor-league rehab assignment this weekend; but, as a 36-year-old veteran coming off a major offseason shoulder injury, he’s hardly certain to possess the raw stuff required to succeed in October.

And while Miller does possess that natural talent, highlighted by his triple-digit fastball, he is slated to begin the second half of the season back in triple A, aiming to clean up the inconsistencies in his delivery that led to an ERA over 8.00 in seven starts this year.

Normally, this is where a contending team would look to the trade deadline for answers and target a front-line arm to bolster its postseason pitching plans.

After all, during the Dodgers’ 22-22 stretch over the last 44 games, their starters have a 4.91 ERA, fifth-worst in the majors during that span.

This year, though, the trade market is slim on such impact pitchers.

The Dodgers have interest in Garrett Crochet, according to people with knowledge of the situation not authorized to speak publicly, but the Chicago White Sox left-hander is already nearing an innings limit in his return from Tommy John surgery, meaning it’s unlikely he could pitch regular turns through the rotation between now and October.

Tarik Skubal of the Detroit Tigers is one potential deadline target having a Cy Young-caliber season. But with two and a half seasons of club control left, it’s unlikely the Tigers would move him — and certainly not for anything less than a massive prospect haul, the kind the Dodgers are typically wary of offering this time of the year.

There are other cheaper, yet still productive, potential options — such as the Tigers’ Jack Flaherty, Toronto Blue Jays’ Yusei Kikuchi or White Sox’s Erick Fedde.

Depth, however, is not the Dodgers’ biggest need. In the short term, they can rely on younger arms such as Stone, Knack and Justin Wrobleski to cover innings and preserve the club’s sizable NL West lead.

“I just look at it as these guys are getting a good opportunity in a playoff race, in a pennant race,” Roberts said.

The eventual returns of Glasnow, Kershaw, Buehler, Miller and — at some point — Yamamoto will stabilize their depth chart, as well.

Until then, what’s once again missing is a healthy, established, true front-of-the-rotation arm — the kind that could have tipped the scales in this week’s series against the Phillies, and will almost certainly be needed to key any extended playoff push.

Perhaps Glasnow will return on time and be that pitcher again. Maybe Stone will build off his strong first half of the season and blossom into a true postseason weapon. It’s not impossible for Yamamoto to come back and look like the All-Star-caliber pitcher he was before his injury.

It’s just that, at this stage, none of those outcomes look inevitable. None of those pitchers can be taken for granted.

Once again, the Dodgers are scrambling to reinforce a rotation they thought they had already fixed.

And as it stands now, they might have no choice but to cross their fingers, wait on improved health, and hope they have enough talent on the mound to carry them to — and through — October.

This week’s sweep was a reminder that’s no guarantee.