SAN DIEGO -- The Padres have spent the first month of the season relying on Manny Machado and Eric Hosmer to carry their offense. And, you know what? It might actually be working. Along with a steady diet of pitching and defense, San Diego has ridden two productive offensive weapons to an 18-10 record.

But the simple reality is this: By its very nature, baseball isn’t conducive to that formula. Generally speaking, it doesn’t matter how good your best couple hitters are (and Machado and Hosmer have been as good as any 1-2 punch in the Majors) -- they can’t do it every night. 

When they don’t? Well, it looks something like this. The Padres’ bats fell flat on Saturday night in an 8-0 loss to the Marlins at Petco Park. Miami right-hander Pablo López was outstanding across eight scoreless innings, as San Diego was shut out for the first time this season, limited to five hits, all singles.

• Kim shows amazing athleticism with midair adjustment

“We knew we had our work cut out for us today,” said Padres manager Bob Melvin. “He pitched really well.”

Machado singled and walked, extending his on-base streak to 17 games. Hosmer, meanwhile, failed to reach base for the first time since April 23. It was one of those nights where the Padres’ two biggest bats could’ve used some help from elsewhere. And that help didn’t come.

“Hopefully, I would say today is their starting pitcher,” said Melvin said. “We’ve been doing just enough to win games. But certainly, against a guy like that today, just not enough offensively.”

Of course, it’d be one thing if help were on the way. But right now, Luke Voit does not appear anywhere near game-ready enough to make his return from a biceps injury. Voit began a rehab stint with Triple-A El Paso earlier this week. He is hitless through five games with 12 strikeouts, including punchouts in all five of his at-bats on Saturday.

Knowing their offense was light on thump, the Padres swung a trade to acquire Voit in March. But before his injury, he’d done little to provide the offensive jolt the club needed. Voit was hitting just .143 across 54 plate appearances. His biceps had been barking for some time, so the team shut him down in the hopes that rest and rehab might change things.

“I think he probably got into some bad habits,” Melvin said on Friday. “He was cutting [his swing] off a little bit. What I’ve seen in the past … an area he covered really well at Yankee Stadium – right-center field was a really good spot for him. And I think the injury had a lot to do with that, where he just wasn’t covering the outside part of the plate because he couldn’t extend.”

It’s only five rehab games, of course, as Voit works through some minor mechanical tweaks that the team thinks will allow him to tap into his immense power. If -- the Padres say “when” -- Voit works out those kinks, that’s precisely the type of middle-of-the-order bat this lineup could use.

But even that doesn’t solve the entire problem. Machado is atop the National League leaderboard in hits, runs, batting average, on-base percentage and WAR. Hosmer isn’t too far behind him in some of those categories. But the other seven starters in the San Diego lineup on Saturday night sported batting averages below .230.

As such, the Padres were in trouble the moment starter Sean Manaea surrendered a solo homer to Joe Dunand in the third inning. Garrett Cooper tacked on a two-run double in the fifth, and the San Diego bullpen imploded late. But Manaea was mostly solid across six quality innings, and he saw his velocity spike well above his season average, into the mid-90s. He was simply outdueled.

“Overall, it was good, but it was those two mistakes,” Manaea said. “… And Pablo pitched an unbelievable game.”