A struggling Mariners offense facing one of the National League’s top young pitchers seemed like a bad combination, but nobody told Ty France and José Marmolejos.

Seattle's two midseason additions brought the bats on Saturday as the Mariners snapped a three-game losing streak with a 7-3 victory over the D-backs, with all seven of those runs coming off standout right-hander Zac Gallen.

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France, acquired in a trade with the Padres on Aug. 30, went 3-for-4 with a walk and launched his second home run of the past two games with a 429-foot blast in the first. The 26-year-old infielder has reached base in all eight games played since joining the Mariners and has batted .379 (11-for-29) with six RBIs.

“He’s a good hitter,” Mariners manager Scott Servais said. “He covers the entire strike zone. We’ve seen him drive some balls to the opposite field, and certainly the last couple nights, getting the head out and pulling the ball into the seats. He’s having a nice year, and he really has given us a shot in the arm since we’ve gotten him in our lineup.”

France had a huge year at Triple-A last season, batting .399 with 27 homers in 76 games at El Paso, but he was blocked by Manny Machado at third base and limited to part-time duties at designated hitter this season until he was dealt to Seattle.

The Mariners have given him time at DH, second base and third, and they're eager to figure out how to keep his bat in the lineup going forward. His 446-foot homer in the eighth inning of Friday’s 4-3 loss was the longest this year by a Mariner, and he followed up by putting one nearly in the same spot by jumping on a Gallen curveball in the first inning.

“It’s been nice, getting the consistent at-bats and getting settled at the plate has made a huge difference,” France said. “You come in and contribute right away, it feels good. It’s definitely a confidence thing, knowing you’re going to get the start the next game regardless if you’re 4-for-4 or 0-for-4. Building off that momentum and getting more comfortable at the plate definitely helps a lot.”

Marmolejos, a 27-year-old rookie, was recalled from Seattle’s alternate training site on Aug. 27 when the Mariners needed an extra player for a doubleheader, and he’s earned a permanent stay by hitting .341 (15-for-44) with four homers and 13 RBIs in 13 games. Playing left field on Saturday, Marmolejos went 2-for-4 with a homer, a double and three RBIs.

After signing with Seattle on a Minor League deal, the former Nationals prospect Marmolejos was included on Seattle's Opening Day roster, but he was sent down after batting just .103 with zero extra-base hits in his first eight games. The difference since his return?

“I just think relaxing,” Servais said. “His first go-round with us at the start of the season was his first experience ever in the big leagues. You press a little and want it to happen really bad. Since he came back, he’s been very consistent. This guy has power and can really drive the ball the other way. He can do OK in left field, but it’s the bat that excites us. He can really swing it.”

Gallen set a Major League record by opening his career with 23 starts of three or less runs allowed until giving up four runs in a 4-2 loss to the Giants in his previous outing. But the Mariners jumped on him for four runs in the first and seven in his five frames as the 25-year-old’s ERA rose from 2.29 to 3.15.

Mariners rookie Justus Sheffield was the impressive youngster on Saturday, as the 24-year-old lefty held the D-backs to two runs on five hits. Sheffield equaled his career best by pitching seven innings for the second game in a row, and he flashed his best fastball of the season with his velocity up to 95-96 mph, as he evened his record to 3-3 with a 4.06 ERA in eight starts.

“I’m starting to figure out a little bit more about myself,” Sheffield said. “I’m learning week to week from each outing about how to go about attacking guys and what pitches I’m using. It’s been great to kind of figure out out who I am versus big league hitters.”

With the win, the Mariners hit the three-quarter mark of this shortened season with a 20-25 record and remain 2 1/2 games back of the Astros for the No. 2 postseason spot in the American League West with 15 games remaining.