BALTIMORE—Zac Lowther’s first major league start began well but quickly turned ugly. Lowther, who was promoted from Triple-A Norfolk and is taking Bruce Zimmermann’s place in the rotation as the Orioles try to limit the innings of their younger starters, didn’t make it through three innings.

Lowther allowed seven runs on seven hits in 2 1/3 innings as the Orioles lost their second straight to the Boston Red Sox, 11-6, on Saturday night before 10,598 at Camden Yards, which is the allowed capacity because of Covid-19 restrictions.

In his first major league appearance, Lowther (0-1) pitched a scoreless inning on April 25th against Oakland and then was sent back to the alternate training site at Bowie.

When the Orioles sent Zimmermann down on May 3rd, Isaac Mattson replaced him. Mattson pitched the ninth inning on Friday night, and was swapped out for Lowther.

Lowther pitched a scoreless first on Saturday night but allowed four runs in the second.

“When I was missing, I was missing over the heart of the plate, and with a good lineup like that, you get hurt,” Lowther said. “I wouldn’t say I was nervous per se for this one or anxious. But getting out there, I didn’t settle in right away.”

Michael Chavis’ two-run home run in the second was the big hit. Lowther allowed the first three batters to reach in the third, including a run-scoring single. Shawn Armstrong relieved him with one out and allowed both inherited runners to score.

“I just thought they had a great approach,” manager Brandon Hyde said about the Red Sox. “A major league approach against a left-handed pitcher. The majority of the hits were up the middle, the other way. They stayed on the ball real well.”

It’s a hitting approach Hyde has been preaching to his team, and one that took advantage of Lowther’s inexperience.

“I made a lot of good pitches, maybe not when I need to,” Lowther said. “I’m going to take the good from this and dump the bad. You can always learn from that stuff. I know what I need to do to get better.”

Armstrong, whose ERA is 10.80, allowed two more runs in the fourth, as Boston (21-13) took a 9-2 lead.

Xander Bogaerts hit his seventh home run of the season in the sixth against Rule 5 draft choice Tyler Wells to give the Red Sox an 11-2 lead.

The Orioles (15-18) scored a run in the first against Boston starter Garrett Richards (2-2) on an RBI single by DJ Stewart after Cedric Mullins led off with a hit and stole second to put himself in scoring position. Freddy Galvis hit his fourth home run of the season down the left field line to lead off the second.

Richards, who allowed four runs on eight hits in seven innings, gave up an RBI double to Trey Mancini in the sixth and a run-scoring single by Ramón Urias three batters later.

Besides Armstrong and Wells, the Orioles used Travis Lakins and Tanner Scott, each for an inning, and infielder Pat Valaika somehow got out of the top of the ninth by throwing just five pitches, even after Urias booted Hunter Renfroe’s ground ball to begin the ninth. It was Valaika’s first career pitching appearance.

Hyde said the Orioles are considering adjustments to their staff, but Norfolk is playing in Jacksonville this week, and logistics might make it tricky.

In the ninth, Boston reliever Austin Brice loaded the bases. He hit Urias and Rio Ruiz with pitches and walked Mullins with two outs. Brice also hit Stewart in the eighth. Hays’ two-run single made it 11-6 before Josh Taylor struck out Mancini to end the game.

Mountcastle taking steps: Ryan Mountcastle was hitless in four at-bats one night after his first three-hit game of the season, and his first home run since April 8th.

Last season, Mountcastle hit .333 with five home runs and 23 RBIs. This year, he’s hitting .214 with two homers and nine RBIs.

“Usually, it’s that second year once they finally figure you out, and the weaknesses and stuff, they’re going to try to exploit them,” Mountcastle said. “It’s all about change. I’ve got to change the way I think, change the way maybe I swing sometimes, trying to adapt to the situation, and try to get better from it.”

Mountcastle had a seven-game hitting streak, and Hyde thought he saw more patience.

“I was encouraged [Friday] night. When you think of a 100-mph fastball down and in and hit the ball to right-center the way he did, I figure that means he moving to the baseball the right way,” Hyde said. “Ryan has been quick off the ball, like a lot of our guys.”

Orioles acquire left-hander: The Orioles claimed left-handed pitcher Brandon Waddell on waivers from the Minnesota Twins.

The 26-year-old was 0-1 with an 11.25 ERA in four games with the Twins. In 2020, had a 2.70 ERA in two games with Pittsburgh.

Waddell was optioned to Triple-A Norfolk and right-hander Jay Flaa, who pitched a scoreless 1 1/3 innings in his only appearance with the Orioles, was designated for assignment.

Notes: Dean Kremer (0-2, 6.43 ERA) will face Nick Pivetta (4-0, 3.23) on Sunday afternoon. … John Means was honored by the Orioles before the game for his no-hitter on Wednesday. The Orioles presented him with a watch and made a $10,000 donation in his name to the Boys and Girls Clubs of Metro Baltimore. Jim Palmer, who threw the last solo no-hitter, congratulated him with a video message on the scoreboard. … The crowd was the largest of the season, and the second sellout.