ST. LOUIS -- The Pirates’ longest road trip of the season began Thursday night at Busch Stadium. The 11-day trek, which will take them from the Midwest to the Southwest to the West Coast, will feel even longer with more nights like this one.

Right-hander Joe Musgrove struggled for his second straight start, allowing eight runs while walking a career-high five hitters and only finishing three innings. Pittsburgh’s bullpen, worked heavily the past two days at PNC Park, had another busy evening. And the Cardinals emerged from their recent slump as they thoroughly beat the Bucs, 17-4.

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Musgrove was one of the Majors’ most effective starters in April, when he posted a 1.54 ERA while holding opponents to a meager .192/.244/.296 slash line in 35 innings. His first five starts were all quality outings. He pitched deep into games and gave the Pirates a chance to win every time he stepped on the mound. That hasn’t been the case in May.

In his last two starts, Musgrove has allowed 13 earned runs on 12 hits and seven walks while only pitching 5 2/3 innings. To make it through this road trip against three opponents with winning records, the Pirates will need more out of their rotation no matter how many injuries they’ve sustained.

“I don’t feel like this is going to be a trend for me,” Musgrove said. “I feel like I’m going to turn things around.”

Musgrove said he feels fine physically. But after falling behind half of the 20 hitters he faced on Thursday, he threw a dangerous combination of hittable pitches over the plate and non-competitive pitches out of the strike zone. That led to the six hits and five walks he allowed, but not a loss of confidence.

“I don’t feel like I’m lost; I’m not going to lose sleep over it,” Musgrove said. “I analyze it. I rewatched the game a couple times since I came out; I obviously had plenty of time. I’ll go back to the drawing board, work on a few things, clean up a few things between starts, but I don’t feel like I’m at a point where I’m panicking and searching for something.”

After rewatching his outing, Musgrove said it wasn’t as “sloppy” as it felt on the mound.

“I was close with a lot of pitches,” he added. “But close doesn’t count. You’ve got to execute.”

The walks, though, are concerning for Musgrove. He had never walked more than four batters in a professional game, much less a Major League start, until Thursday. He took it a step farther, saying, “I don’t think I’ve ever walked five people in my life.”

He’s earned his reputation as a strike-thrower. Among pitchers who threw at least 110 innings last season, the right-hander posted the Majors’ 11th-lowest walk rate (4.7 percent) and threw the highest percentage of pitches (50.9 percent) in the strike zone. But after a perfect first, Musgrove put himself in a hole in his final three innings by walking the leadoff man each time. All three eventually scored.

“It wasn’t his night,” manager Clint Hurdle said.

The Cardinals followed Marcell Ozuna’s leadoff walk in the second with a single and consecutive doubles, and Paul Goldschmidt capitalized on Matt Carpenter’s two-out walk by punching an RBI single to center field.

The Cards did not hit Musgrove hard in the third, but another leadoff walk to Ozuna came back to haunt him after a flyout, back-to-back singles by Yadier Molina and Dexter Fowler and a run-scoring grounder hit by Kolten Wong.

"We got some good pitches to hit and did something with them,” Fowler said.

Musgrove threw 69 pitches in his first three innings but returned for the fourth, only to walk Carpenter and Goldschmidt. The Cardinals continued to practice patience against right-hander Clay Holmes. Holmes walked two of the first three hitters he faced and wound up allowing three runs (two earned) in two innings of work.

That put the bullpen wheel in motion, and each spin was a reminder of the Pirates’ fading depth. Holmes was in Triple-A until Thursday morning. Right-hander Dovydas Neverauskas, recalled last Saturday, allowed five runs in the sixth inning.

Making his Major League debut, right-hander Montana DuRapau pitched a perfect seventh before giving up a run on three singles and a groundout in the eighth.

“What we saw versus what he felt, they’re not even close,” Hurdle said of DuRapau. “Composure. Attack. Pitch efficient, still. Good for him.”

Maybe the most encouraging development for the Pirates in a lopsided loss: Gregory Polanco seems to be rediscovering his power stroke. After hitting his first home run of the season on Tuesday night, Polanco went deep to right in his first at-bat against Michael Wacha on Thursday and finished 3-for-4 with two doubles and a walk. It was Polanco’s third career game with three extra-base hits and his first such performance since June 8, 2016.

“A bunch of good swings,” Hurdle said. “It’s all been fun to watch, him getting traction in the box. … Very fun to watch.”