Orioles right-hander Zach Eflin was placed on the 15-day injured list with lower back discomfort, Baltimore announced Monday. The move comes one day after interim manager Tony Mansolino hinted that a stint on the injured list was likely.

This is Eflin’s second trip to the injured list this season. The previous time was for a strained lat muscle.

Eflin has struggled since returning from the lat injury, and with four runs against him in one inning Saturday against the Tampa Bay Rays, his ERA rose to 5.95. Since returning from the lat injury in early May, his ERA is 7.16 in nine games. He’s surrendered 14 home runs in that span.

The pitcher felt his back tighten during his pregame bullpen session Saturday. He felt he could pitch through it, but the immediate results proved otherwise. Mansolino quickly pulled the 31-year-old. The Orioles lost to the Tampa Bay Rays 11-3.

When Eflin arrived at Camden Yards on Sunday, his back remained stiff. He said he didn’t know whether an injured list stint would be necessary because he hadn’t yet met with the training staff. About an hour later, Mansolino said he presumed Eflin would be headed to the shelf.

“Most likely, it’ll trend toward an IL here in the next 24 hours, would be my guess,” Mansolino said. “Depending on how today goes, we’ll make the next move in accordance to that.”

In 2023 and 2024 Eflin spent time on the injured list with back issues, but this is the first time this season Eflin has felt the discomfort.

To replace Eflin, the Orioles recalled right-hander Brandon Young. Because he replaced an injured player, Young wasn’t subject to the 15-day stay following his option back to the minors. Young started for the Orioles on Wednesday against the Texas Rangers, and he allowed four runs in four innings.

Since Eflin arrived in Baltimore last season ahead of the trade deadline, he has been a valuable member of the rotation. He posted a 2.60 ERA in 55 1/3 innings for the Orioles to end last season. This year, his performances have been shakier, although the lat injury and back discomfort likely have played a role.

Ahead of Saturday’s game, Eflin said he felt an obligation to pick up innings for the bullpen.

“I knew something wasn’t right, but I couldn’t necessarily blindside them like that, and I was able to deliver a pitch,” Eflin said. “Wasn’t comfortable, but it kind of gets to a point where, once you stop moving around, it just locks up and tightens up, and you can’t do much about it at that point. So I tried to keep moving as much as I could from the bullpen to the game, and I was able to deliver pitches.”

Other news and notes

• The Orioles reshuffled their bullpen by selecting the contract of right-hander Matt Bowman and optioning right-hander Kade Strowd to the minors. To make room on the 40-man roster for Bowman, Baltimore activated right-hander Luis F. Castillo from the minor league injured list and designated him for assignment.
• Infielder Jordan Westburg, who aggravated his left index finger sprain Friday, remained out of the lineup Monday. Mansolino said after Sunday’s game that Westburg’s batting practice session earlier that day didn’t go as well as hoped.
• Catcher Adley Rutschman, who’s on the injured list for the first time in his career, said his oblique strain is progressing. He is throwing but hasn’t swung a bat. Rutschman didn’t offer details on when the issue cropped up, but he spoke to trainers about it prior to last week’s series opener against the New York Yankees. Mansolino presumed Rutschman would be out until after the All-Star break.
• Catcher Maverick Handley remains in concussion protocol. Mansolino said Handley will be out for “a little while.” Handley has experienced multiple concussions, Mansolino said, so they’re being especially careful.