MINNEAPOLIS — This all took longer than Ryan Mountcastle had anticipated. The improvement he felt one day would give way to a relapse the next, with lightheadedness and dizziness rendering the Orioles first baseman unable to connect with a baseball that looked pea size — and unable to stay on the field.

But on Sunday Mountcastle stood in front of his locker in the visiting clubhouse of Target Field, reinstated yet not in the starting lineup for the final game of Baltimore’s series against the Minnesota Twins.

He smiled easily, because the vertigo that has plagued him since early June finally has subsided. Although there’s frustration at having not played a major league game since June 8, there’s also relief that a return is upon him.

“This feels like the longest I’ve ever gone without playing,” Mountcastle said. “It wasn’t fun at all, and just happy to be back and feel like a normal human again.”

With the Orioles routing the Twins, Mountcastle delivered an RBI single during a seven-run fifth inning as a pinch hitter. Colton Cowser replaced him immediately as a pinch runner.

Mountcastle said this is the first time he’s dealt with vertigo. It hit him “in waves,” he said. Once his heart rate increased, he would start getting “loopy, lightheaded and whatnot,” he said. “It wasn’t fun, that’s for sure.”

The 26-year-old also said there’s no way of knowing whether this will flare up again.

The onset of his symptoms began in Milwaukee against the Brewers. He played two games there and finished 0-for-4 in both, playing through the lightheadedness, dizziness and nausea he began to experience on the field. After his last game, Mountcastle told the Orioles something was wrong.

Mountcastle remained out of the lineup for another five days before Baltimore placed him on the injured list June 13. A week later, he started a lengthy rehab assignment with Triple-A Norfolk, where he began 0-for-14 as he navigated symptoms.

“I feel like the ball was a pea size and was just blowing by me for a couple games there,” Mountcastle said. “I was like, ‘This doesn’t feel right.’ I let them know there’s something wrong. It sort of affected my performance for a couple games. Now I’m feeling better and seeing the ball better.”

Between games, Mountcastle said, he did Epley maneuvers — a series of slow head movements aimed at alleviating vertigo — and took medication.

With Norfolk, Mountcastle hit .222 in 12 games with 17 strikeouts. He clubbed one home run and notched a double for his only extra-base hits. His performances improved; in his final eight games, Mountcastle hit .300.

“The first series I still felt a little weird, but in Norfolk and Durham I felt like I was seeing the ball a lot better,” Mountcastle said.

To make room for Mountcastle on the active roster, Baltimore optioned left-hander Bruce Zimmermann to Triple-A. The move left the Orioles with one fewer pitcher than the maximum they can carry (13) on the final day of the first half, but with the All-Star break beginning Monday, they have time to rest their arms and adjust their roster for the second half.

Without Mountcastle, Ryan O’Hearn has received most of the playing time at first base against right-handed pitchers. When asked what Mountcastle’s reinstatement might mean for O’Hearn — who’s hitting .307 — manager Brandon Hyde said, “not much.” Having 14 position players he’d like to give at-bats to is a good problem, Hyde added.

Standing at his locker, Mountcastle found it hard not to smile now that he’s back with the major league team.

“We’re playing really well, and I want to contribute,” Mountcastle said. “But it is what it is, and just happy to be back now.”

andy.kostka@thebaltimorebanner.com