OAKLAND, Calif. — Sitting down the right field line Friday night, under an awning in the old-fashioned bullpen area at the Coliseum, Cole Irvin looked out at a sparse group of Athletics fans.

It wasn’t long ago when he’d see at least half of the green seats filled, if not more. The 2021 season, the last time Oakland finished above .500, drew the passionate supporters in bulk. The 2022 Bay Bridge Series was as electric as anything Irvin experienced, when the left-hander pitched in the second of his two seasons for the Athletics.

The scene Friday was far from the near-distant excitement, but Irvin still soaked in the hulking structure that at best can be called unique and at worst be labeled dilapidated. This is Irvin’s last trip to the Coliseum. It’s the Orioles’ last series here before the Athletics move temporarily to Sacramento and, eventually, head to Las Vegas.

Soon, this historic stadium will hold no fans at all.

“The fans are there in Oakland. They’re there for the A’s. I just feel for them, having that stripped away from them,” Irvin said. “It’s a historic franchise in that city, and baseball’s going to be missed dearly in that area. The argument is: You can always be a Giants fan. When you bleed green and gold, those fans are real, those fans are honest. They bleed green and gold. You know who those fans are. To me, there’s something special about that uniform and the fans and the unique relationships that come out of there.”

Irvin has the closest connection to this stadium because he used to play here, but others on the Orioles have visited throughout the years.

Manager Brandon Hyde grew up as more of a Giants fan but attended Athletics games with his father during the franchise’s heyday, when the likes of Rickey Henderson, Carney Lansford and the Bash Brothers made this team great.

“You know what I like about it the best? It’s the only dugout still where everybody can sit and watch,” Hyde said. “All these dugouts nowadays, they have the rail in front — and rightfully so, ’cause you can get blasted. But you’re so far away from the field there that you can have the dugout like the old-school ’80s dugouts where you can kind of just sit on the bench and watch. I love that about it.”

Utilityman Ryan O’Hearn has spent his whole career in the American League, so he’s visited the Coliseum for a series each year.

He knows the groundskeeper’s dog, Reba, and gave her a belly rub in the clubhouse before the game. O’Hearn remembers playing a game here when the yard lines were on the baseball field, because the Raiders had played a game the day before — and then the Raiders moved to Las Vegas, too.

“Just so much different from every other stadium that you have to appreciate it for what it is,” O’Hearn said, before looking around at the state of things now.

“It’s like walking into a mall that was awesome 10 years ago and now all the stores are boarded up and there’s, like, an antique shop in the corner that’s still open, but that’s about it,” O’Hearn said.

A flag that read “SELL” hung in the right field seats, a reference to owner John Fisher, who has enraged fans in this city and failed to find a deal to keep the Athletics in Oakland.

The upper outfield sections have been empty for years. They have tarps over the seats, an unsuccessful attempt to mask the great nothingness that looms high above the field of play. The bullpen mounds face away from the field, leaving warming relievers to place their trust in whomever is guarding their back against errant line drives. The elongated foul territory is a pitcher’s friend and hitter’s nightmare.

Catcher James McCann circled this series when the schedule came out almost a year ago, because he wanted his young kids to experience the one-of-a-kind nature of baseball at the Coliseum. His twins, Christian and Kane, have been here before as 3-year-olds during the 2020 postseason.

“Just so much different from every other stadium that you have to appreciate it for what it is.”

Orioles utilityman Ryan O’Hearn

They’re now 6; they may have a better chance of remembering a weekend here in the years that follow, and they’ll at least have photos commemorating a final season at the Coliseum.

“I’ve been here when the ballpark was pretty full, and it’s a place that’s been here a long time,” McCann said. “A lot of players have come and gone in this ballpark, in this stadium. It’s one of those things that’s sad to know this is it.”

Baltimore has a history here. The Ravens won an AFC championship game here against the Raiders in 2001, leading them to their first Super Bowl title. The Orioles closed out a sweep of the 1971 American League Championship Series at the Coliseum. In 1991, four Orioles pitchers combined to throw a no-hitter against the Athletics. Gunnar Henderson had a chance at the cycle last year but stretched a single into a second double instead.

Irvin will remember the confines as a place of joy. He learned how to handle the up-and-down nature of major league pitching here as he covered 359 1/3 innings for Oakland. He laughed as he recalled a game he played with other Athletics starters, seeing who could sit still longest as a foul ball sailed into the rail-less dugout.

He’ll have two more games to bask in memories before the Athletics leave. Then the Coliseum will sit quietly, a memorial for all that was and all that will be missed.

“For me, there really isn’t a bad thing to say about Oakland,” Irvin said. “It’s going to be fun to pitch there one more time.”