Boston’s Kevin Pillar slides into third with a stolen base as Orioles third baseman Rio Ruiz fields the throw in the sixth inning Sunday. Ruiz drove in four runs to lead Batlimore to a 5-4 victory. Tommy Gilligan/Associated Press

BALTIMORE — Rio Ruiz drove in four runs, Thomas Eshelman provided exceptional relief for injured starter Wade LeBlanc and the Baltimore Orioles beat the Boston Red Sox 5-4 Sunday to earn a split of the four-game series.

Ruiz came in batting .161 in August and was dropped to the No. 8 slot in the lineup, from where he singled home two runs in the third inning and delivered a two-out, two-run double in the seventh.

“I understand what I’m going through. It’s frustrating,” he said of his slump. “But I was glad I was able to help out the team today.”

Anthony Santander stretched his hitting streak to 18 games and highly touted prospect Ryan Mountcastle doubled twice in his third game with the Orioles, who climbed back to .500 (14-14) with their second straight win following a six-game skid.

After Boston’s Kevin Pillar homered on the game’s second pitch, LeBlanc faced three more batters before leaving with left elbow stiffness. The extent of the injury was unclear and a bit surprising, given that the crafty left-hander had pitched in a combined 108 games over the previous three seasons.

Manager Brandon Hyde said LeBlanc would get an MRI on Monday.

Eshelman (2-0) entered and walked Christian Vazquez, then retired the next 13 batters as Baltimore built a 3-1 lead against the last-place Red Sox.

“Tommy won us the game, getting those 13 outs,” Hyde said. “Just a really great job of pitching.”

Eshelman had never before come into a situation where he received all the time he needed to warm up after replacing an injured pitcher.

“It was definitely an interesting experience,” he said. “I was just trying to get to the fifth inning because we had some arms in the bullpen. I was hoping they would pick me up, which they did.”

Miguel Castro started the sixth and immediately gave up a single to Pillar, Boston’s first hit since the leadoff homer. Xander Bogaerts doubled in a run before Michael Chavis struck out with two on and two outs.

Ruiz gave the Orioles some breathing room in the seventh with a double to left following singles by Pedro Severino and Chance Sisco.

“Those couple of add-on runs were enormous,” Hyde said. “Look at the final score. Those were some big RBIs.”

Tanner Scott gave up a two-run homer to Jackie Bradley Jr. in the ninth before getting the final out for his first career save.

Baltimore went ahead 3-1 in the third inning against Zack Godley (0-3) and Jeffrey Springs. Three walks loaded the bases before Springs came in and gave up a two-out single to Ruiz. Andrew Velazquez then dropped a two-out bunt single down the third-base line that brought in Mountcastle.

Godley allowed only two hits, but was done in by five walks.

“He knows how many walks he had today so he’s concerned about it,” Manager Ron Roenicke said. “Those walks hurt, no question.”

The defeat gave Boston a major league-high 20 losses compared to only nine wins.

“It’s tough when you expect to win and you don’t and you start off poorly, which we did. We’re trying to get some things going,” Roenicke said. “We got a little better when we won three in a row (including the first two games of the series), real close yesterday (a 10-inning loss), close again today.”

STREAK IS ON

Santander kept his career-best hitting streak alive with a fourth-inning double. It’s the longest run by an Oriole since Nick Markakis hit in 18 straight games in 2014.

TRAINER’S ROOM

Red Sox: Roenicke said outfielder Andrew Benintendi (rib cage strain) has a way to go before being ready to return, but he is counting on having Benintendi back. “I know these things take a long time to heal, but I’m expecting it, yes,” the manager said.

Orioles: Severino left in the seventh because of right hip flexor tightness.