Stewart Thalblum grew up around the Oakland Athletics as the son of the visiting clubhouse manager.

Now the 21-year-old is pondering the next phase of his life as he prepares for another season as a batboy for the A’s.

“It’s just gone by so fast, working all these seasons and grinding them through,” Thalblum said. “I look up, and I’m like, ‘This is the end.’”

Thalblum lives in the Bay Area and has been a batboy since he was 18, but handling some sort of duty at Oakland Coliseum since he was 8 because his dad, Mike Thalblum, has worked for the A’s since before he was born.

The younger Thalblum also goes to spring training in Mesa, Arizona, where he is wrapping his second stint of roughly six weeks in a full spring with the A’s.

Thalblum says what fans see — batboys in the team’s uniform running to and from home plate while handling other responsibilities around dugouts during games — is a small portion of their day.

The typical day at spring training for Thalblum starts around 7 a.m. and ends roughly 12 hours later. Batboys help take care of food and laundry, and maybe run errands for players. Basically, whatever the players need.

“Our goal is to make sure that when they show up at the ballpark every day, all they have to do is focus on playing baseball,” Thalblum said.

When the A’s break camp, there will be exhibition games at home and across the bay in San Francisco, where Thalblum says he also works when the A’s play there. Then the first seven games of the regular season will be at Oakland Coliseum.

“I did the math the other day,” Thalblum said. “By the time the team goes on the road for the first time in early April, it’s going to be 49 out of 51 days straight for me.”

Thalblum played high school baseball, and since then, he’s been an online student at Arizona State. He’s graduating this year with a degree in sports business and would love to work in the front office of the A’s — even after the team moves to Las Vegas, assuming that deal goes all the way through.

His status as an online student gives Thalblum the flexibility to go to spring training with the A’s, but don’t mistake that for making it easier to juggle both.

“It’s a big time management thing,” Thalblum said. “It’s a lot of late nights for me. It’s going to be worth it, and I’m already seeing it pay off.”

Thalblum isn’t sure, but guesses he is slightly younger than the average batboy. Joseph Ortiz is a 27-year-old who lives in Los Angeles and is working as a batboy for the Dodgers in Arizona this spring.

For Thalblum, it’s a chance to be around a team he grew up loving, and create relationships with players that can last well beyond his time as a batboy.

“It’s getting to know these players as people,” Thalblum said. “These guys are people first, and their job just happens to be playing baseball.”