SAN DIEGO — Zac Gallen struck out nine in six innings, allowing one unearned run in a road trip-opening 6-3 win over the Padres on Monday, July 7 at Petco Park.

Gallen (7-9) left the game with a 4-1 lead, then the Padres made it 4-2 in the bottom of the seventh inning against reliever Kyle Backhus. Backhus, however, got out of further trouble by inducing Jackson Merrill to foul out to third base.

Corbin Carroll’s triple, one of two extra bases for the Diamondbacks All-Star, and Geraldo Perdomo’s base hit, both with two outs in the top of the eighth, provided insurance runs for a bullpen minus its closer. Shelby Miller was placed on the injured list before the game.

The Diamondbacks needed them, as Manny Machado, who reached 2.000 hits for his career in the fourth inning, homered off Backhus leading off the eighth.

The Padres had a golden opportunity with one out after reliever Juan Morillo, called up from Triple-A Reno earlier in the day, walked the first two batters he faced to load the bases.

Morillo then got José Iglesias to pop out to shortstop and struck out pinch hitter Elias Diaz with a 100 mph, 3-2 fastball.

Morillo shouted and pumped his arms in celebration.

Kevin Ginkel, who’s had an up-and-down season — including being sent to Triple-A for a spell in late May after early-season struggles — was the chosen closer.

After Ginkel issued a leadoff walk in the ninth, Alek Thomas delivered a potentially game-saving defensive play in center field. Thomas flagged down a Merrill fly ball on the warning track.

Machado grounded into a 5-4-3 double play to earn Ginkel the save in a game manager Torey Lovullo called a “gut-check win” on the broadcast.

Josh Naylor’s 11th home run of the season, a two-run shot in the top of the fifth, gave Arizona some breathing room in a one-run game.

A walk to Naylor, followed by Eugenio Suarez’s run-scoring double, tied the game at 1 in the second inning, after the Padres scored a run in the bottom of the first against Gallen.

Carroll led off the third with a double and scored on a one-out single for a 2-1 Diamondbacks lead.

Gallen rebounded from the first inning and has held the Padres scoreless for the next five, striking out the side in the bottom of the fifth.

Shelby Miller to injured list, Ketel Marte day to day

The injuries within the Diamondbacks continue to mount, and the bullpen suffered another one before the team’s game against the Padres on Monday, July 7.

Miller was placed on the 15-day injured list with a right forearm strain in an announcement made less than an hour before first pitch, retroactive to July 6. Morillo, optioned to Triple-A Reno on July 1, was recalled to replace Miller on the active roster.

Miller (3-3, 1.98 earned run average) has 10 saves in 15 chances, and most recently pitched on July 5 at Chase Field against the Kansas City Royals, throwing a scoreless inning. He’s appeared in 37 games this season.

Morillo returned after having spent more than two months in the major leagues with Arizona. He is 0-2 with a 3.91 ERA in 29 games after his clutch performance on Monday.

The Diamondbacks bullpen lost reliever Ryan Thompson to a strained scapula on July 6 when he was placed on the 15-day injured list, and right-hander Kendall Graveman is still working his way back from a right hip impingement.

Before announcing the Miller injury, the Diamondbacks made a late lineup change, removing All-Star second baseman Ketel Marte from the batting order with right groin tightness and inserting Blaze Alexander.

Marte was scheduled to bat second. Instead, players in the lineup were moved up in the order, and Alexander batted ninth.

Alexander got his fourth start in the past five games, playing second base for the third time. Marte did not play July 5 and was used as the designated hitter July 3.

The Diamondbacks announced that Marte was given a day off for recovery and is expected to be day-to-day as far as his playing status.

Naylor was in the Diamondbacks’ lineup on Monday, July 7, playing first base and batting fourth. But Naylor continues to play through a lot of “bumps and bruises,” manager Torey Lovullo said.

“But he continues to want to go out there and perform, help this team win baseball games,” Diamondbacks manager Torey Lovullo said prior to the four-game series opener against the Padres at Petco Park.

“Those are two things that stand out to me,” Lovullo said, also mentioning Carroll, who is playing through a broken wrist bone. “The guys that are banged up aren’t letting it happen where it’s going to take them out of the lineup. They want to go out there and play.”

Carroll returned on Saturday, July 5, but was 0-for-9 with five strikeouts in his first two games back from the injured list on July 5 and 6.

“I just appreciate what he’s trying to do,” Lovullo said of Carroll. “His hand has healed enough to where it’s not going to do any more damage. I keep asking him how it’s going and he said ‘fine.'”

Coming up

Tuesday, July 8: At San Diego, 6:40 p.m., Diamondbacks RHP Merrill Kelly (7-4, 3.55) vs. Padres RHP Nick Pivetta (9-2, 3.25).

Wednesday, July 9: At San Diego, 6:40 p.m., Diamondbacks RHP Brandon Pfaadt (8-6, 5.42) vs. Padres RHP Dylan Cease (3-8, 4.62).

Thursday, July 10: At San Diego, 6:40 p.m., Diamondbacks LHP Eduardo Rodriguez (3-5, 5.78) vs. Padres RHP Randy Vasquez (3-4, 3.79).

(This story has been updated to add new information.)