The player the Orioles’ clubhouse considers the glue of their lineup and a veteran stalwart have both returned.

Third baseman Jordan Westburg, who has been on the injured list since April 28 with a left hamstring strain, and center fielder Cedric Mullins were reinstated from the injury list Tuesday. In corresponding moves, the Orioles optioned outfielder Heston Kjerstad to Triple-A Norfolk and designated infielder Emmanuel Rivera for assignment.

Jorge Mateo was also added to the injured list later on Tuesday with left elbow inflammation. It’s the same elbow he had Tommy John surgery on last year. He has felt discomfort since colliding with Kjerstad on May 31, though an MRI showed no structural damage. As a corresponding move, the Orioles selected infielder Luis Vázquez’s contract from Triple-A.

Additionally, Matt Bowman cleared waivers and accepted an assignment to Triple-A Norfolk.

Westburg, who started experiencing minor aches and pains midway through spring training, reported soreness in his hamstring after playing both games of a doubleheader in April. He was placed on the injured list a full two days later, then suffered a setback in mid-May, halting his recovery. He said he felt like he wasn’t ready to handle the workload yet, so was shut down until the hamstring calmed down again.

He began his rehab assignment at the end of May and played in eight games for Triple-A Norfolk, where he had 11 hits, including six for extra bases, in 28 at-bats. Prior to the injury, Westburg was hitting .217 with the Orioles. The IL stint also gave him a chance to heal the other ailments that were bothering him earlier in the season, he said.

“I want to say relief but I’m excited to be back,” Westburg said. “Way too long on the IL for my liking and I was itching to play some baseball again, so happy to be here.”

As for being considered by interim manager Tony Mansolino to be the glue of the lineup, he said that’s an honor to hear.

“I’d call him a liar to his face,” Westburg joked, before adding, “It’s flattering, certainly. I’m one to try to keep the spotlight off myself and not think too highly of myself, so for somebody else, someone who’s manning this ship right now and who I have a really good relationship [with to say it], it means a lot. It makes you feel good about yourself. It makes you feel wanted and somewhat needed in this clubhouse.”

Westburg, an All-Star a year ago, should spend most of his time at third base, with Jackson Holliday at second and Gunnar Henderson at shortstop. Coby Mayo, who should have an extended chance in the majors with Ryan Mountcastle out for two months, will focus mainly on first, Mansolino said.

Mullins, who went on the injured list in late May with a right hamstring strain, did not require a rehab assignment. The 30-year-old still leads the team in home runs (10) and provides defensive stability in center field.

The biggest challenge to coming back and trying to pick up where he left off is “just rhythm,” Mullins said.

“You get into grooves and you don’t really want to get out of them,” he said. “Injuries kind of obviously take that away from you. It’s a matter of continuing to stay process-oriented, to feel the movement.”

The return of Westburg and Mullins helps the Orioles inch closer to full strength. Colton Cowser and Ramón Laureano were activated last week, and Tyler O’Neill and Gary Sánchez are on rehab assignments. Getting those players back will also mean more tough decisions, like the Orioles had to make with Kjerstad.

This was Kjerstad’s longest stint in the majors, and he struggled both at the plate and defensively. He hit .192 with just two home runs, leading to a -1.4 bWAR. Mansolino said they sent Kjerstad down with directives on changes and adjustments to make — the specifics of which he declined to share — and that he showed a level of understanding and self awareness during the meeting.

“I think what we didn’t want to do is say, ‘Hey, go get them,’” Mansolino said. “That’s obviously not the right message when a guy struggles here, as talented as Heston, as good as this can can be, there’s something that we’re missing.”