SAN FRANCISCO -- Early exits by batterymates Anthony DeSclafani and Buster Posey loomed large in the Giants’ 8-0 blowout loss to the Dodgers on Wednesday night at Oracle Park.

DeSclafani couldn’t get out of the third inning in another rough start against the Dodgers, but more concerningly, Posey was forced to depart after taking a foul tip off his mask in the top of the second inning.

• Box score

Posey, 34, visibly grimaced when he was struck by a foul tip off the bat of Dodgers center fielder AJ Pollock. Backup catcher Curt Casali entered the game in the top of the fourth to replace Posey, who began to experience some dizziness but was not immediately diagnosed with a concussion. Manager Gabe Kapler said Posey was feeling better after the game and would be re-evaluated on Thursday.

San Francisco’s bats were overmatched by Dodgers ace Walker Buehler, who allowed only three hits over seven innings to even this three-game series and set up a rubber match for Thursday afternoon’s finale. The defeat cut the Giants’ lead for first place in the National League West to two games.

“Buehler’s one of the best pitchers in baseball, so he’s going to beat most teams,” Kapler said. “He’s going to be successful against most teams, but we have a high standard for ourselves. We expect to be more competitive than we were tonight. We have to figure out ways to adjust so that the next time we see him, we’re better than we were tonight.”

DeSclafani entered Wednesday with a 2.87 ERA and has emerged as the Giants’ No. 2 starter, behind ace Kevin Gausman, but he’s struggled to solve the Dodgers this season. The 31-year-old right-hander opened his outing with two scoreless innings, but the Dodgers chased him by forcing him to throw 40 pitches in a four-run third.

Chris Taylor kicked off the rally with a one-out, nine-pitch walk against DeSclafani, who threw a 3-2 pitch that appeared to clip the bottom of the zone, but was instead called ball four by home-plate umpire Jim Wolf. Taylor came around to score on back-to-back singles by Max Muncy and Justin Turner, and the Dodgers extended their lead to 3-0 on Will Smith’s two-run triple to right-center field.

“He put a really good at-bat together against me,” DeSclafani said of Taylor. “I thought he fought off a lot of good pitches. The borderline call didn’t go my way. With two strikes, you’ve got to induce weak contact or try to turn over Muncy’s at-bat. I just wasn’t able to do that.”

DeSclafani retired Cody Bellinger on a flyout for the second out of the inning, but he yielded another RBI single to Pollock and then walked Matt Beaty, bringing his night to an end. He was charged with four runs on six hits over 2 2/3 innings, marking the second time he’s been unable to complete three innings against the Dodgers this season.

“I think Anthony just kind of ran out of gas there at the end,” Kapler said. “We ran out of pitches for him. But yeah, he did make some mistakes and missed with some locations. It’s a really good hitting team, and they’re going to punish those mistakes.”

DeSclafani delivered another clunker against Los Angeles on May 23, when he allowed a career-high 10 runs over 2 2/3 innings at Oracle Park. Overall, he’s 0-3 with a 9.43 ERA in five starts against the Dodgers this year, compared to 10-2 with a 1.78 ERA in 16 starts against everyone else.

“They grind out at-bats,” DeSclafani said of the Dodgers. “They obviously have a good plan. It’s obviously a really good lineup. It’s for sure frustrating, but at the same time, it’s a challenge. I always look forward to challenges. I’m going to keep pressing on and try to make adjustments. Hopefully I can string together better innings in the future and [give] my team a better chance to win the ballgame.”

The Dodgers continued to pour it on in the late innings, breaking the game open with a three-run seventh and capping their offensive output on Bellinger’s solo blast in the eighth.

The Giants are guaranteed to head into Friday’s 1 p.m. PT Trade Deadline in first place, but president of baseball operations Farhan Zaidi has said he would like to add more pitching depth, particularly to the starting rotation, which currently ranks fifth in the Majors with a 3.34 ERA.

Nationals right-hander Max Scherzer is one of the biggest names available on the market, and he’s reportedly willing to waive his no-trade rights to join a contender, with the three NL West heavyweights -- the Giants, Dodgers and Padres -- viewed as his preferred destinations.

San Francisco doesn’t have an obvious opening in its starting rotation, which already includes Gausman, DeSclafani, Alex Wood, Johnny Cueto and Logan Webb, but landing an experienced starter like Scherzer could add more firepower to the pitching staff and boost the Giants’ chances of ending the Dodgers’ eight-year reign atop in the NL West.

“If I was a player, I’d want to play in San Francisco,” Kapler said. “I think this is a great city, and we are a pretty driven, hungry franchise with an equally hungry and driven fanbase. We’re going to work really hard to get better, and I think any player would want to be a part of that.”