PITTSBURGH -- The Phillies have begun to make moves to bolster their pitching staff, with the reported agreement to terms with starter Drew Smyly and the acquisition of reliever Mike Morin. But manager Gabe Kapler said he thinks the “regulars in our lineups” need to be the spark to lead the Phillies in a playoff push.

“I think the track records of our players suggest that we’re best suited to win baseball games through run production,” Kapler said Friday.

But on Saturday, the offense left the field at PNC Park quietly, having recorded only three hits in a 5-1 loss to the Pirates.

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“I didn’t think we swung the bats the way we’re capable of swinging the bats,” Kapler said after the game.

Those regulars in the lineup that Kapler reference largely went quiet. The Nos. 3-5 batters -- Bryce Harper, Rhys Hoskins and J.T. Realmuto -- went a combined 0-for-11 (including four strikeouts for Realmuto). And the only run that crossed the plate for Philadelphia was unearned.

The need for a run against Pirates starter Joe Musgrove, who allowed no earned runs over six innings, was so strong that the Phillies elected to hit for Zach Eflin in the top of the fifth with Nick Williams. He struck out, then Scott Kingery did, too, stranding Cesar Hernandez at third.

“We were committed to tacking on an additional run there,” Kapler said. “Obviously, you send up Zach to the plate right there with a runner on third base and less than two outs, and he strikes out, you’re not getting any closer to winning that baseball game.”

That decision was also punctuated by a “heavy” feeling that Eflin said he’s been dealing with, a feeling he said there’s “no explanation” for. But Kapler and his staff are seeing its effects over the past few starts.

“The stuff is just getting a little bit lighter, or it’s been a little bit lighter than it was earlier in the season,” Kapler said. “I think that’s something that we have to pay attention to, and talk about how to get his body feeling energetic and moving towards the plate with intensity all the way through his outing.”

But with the way the Phillies swung the bats on Saturday, whether Eflin stayed in or not likely wouldn’t have affected how the game turned out. The team’s three-hit mark for the game was tied for the third-fewest knocks they’ve produced in a game on the season.

Their struggles to gain ground on Musgrove as the game progressed also highlighted a concerning trend for Philadelphia. While most data suggests that the third time through the order becomes more difficult for a pitcher, the Phillies’ OPS has actually dropped as they move from second to third time through. Entering Saturday’s action, Philadelphia batters had produced a .760 OPS the second time through against a starter, then that mark fell to .748 the third time.

It showed on Musgrove's final three strikeouts of the night, which came on Philadelphia's Nos. 1, 3 and 5 hitters' third plate appearances. Though Kapler said more went into Saturday’s issues at the plate, he said one way that’s proven successful to combat that is to work up a starting pitcher’s count early.

“We have seen some times where, in the first inning, we wear a pitcher down and we see 25 pitches or so,” Kapler said, “and then the next time through it’s just a little bit lighter and a little bit lighter, and he survives. And I think we can do a better job of maintaining that grind in the first couple of innings throughout the game.”

The Phillies added big names like Harper, Realmuto and Jean Segura in the offseason, largely to make life tough for opposing pitchers. Kapler believes that core group, which also should include Hoskins, needs to do just that for the team to play its best baseball.

But the manager also stressed that the only way to fuel a stretch of baseball that can help Philadelphia gain ground in a tight National League is to find harmony between the arms and the bats, a unity that’s been up and down as the season has carried on.

“Ultimately, when things are happening all at once, we win baseball games in bunches, and it feels really good,” he said. “But it’s a constant work in progress, without question.”