MESA, Ariz. -- Max Muncy joined the A’s at the Oakland Coliseum for a pregame workout last July after officially signing out of high school. That day, you could see the skills that made him a first-round Draft pick. However, the size difference between him and established big leaguers was apparent.

The version of Muncy roaming the grounds at the A’s Minor League Complex these days would blend in a lot more. The 19-year-old shortstop, whom the A’s made their top pick with the 25th overall selection in the 2021 MLB Draft, arrived early for his first Minor League Spring Training with extra muscle mass added to his 6-foot-1 frame.

In other words, he treated the offseason as bulking season.

“The focus was just getting some more size,” said Muncy. “I’m a younger guy, so putting weight on was a big thing. I came into rookie camp in July at 177 [pounds] and now I’m around 192. Big weight gain.”

It wasn’t as simple as increasing the number of weight plates on each side of the barbell. There’s a certain science to putting on muscle, especially for a teenager whose body is still maturing.

One of Muncy’s main workout locations this offseason was SportsWest Performance in Westlake Village, Calif., which is about 15 miles south of his home in Camarillo. Working with performance director Woody Cliffords, whose large list of former baseball clients include Ryan Braun and Nick Swisher, the two developed a plan specifically to find the right amount of weight that would help Muncy maintain a durable build while preserving his mobility.

“If you’re 26 [years old] and then you put on 20 pounds, that’s a little different,” said Muncy. “It was more just growing into my body and trying to figure out how to gain weight without forcing it on.”

The difference in weight is visible, especially when you look back at Muncy’s wiry body in the many highlight videos that exist from his standout amateur career at Thousand Oaks High School. It’s audible during batting practice sessions, with a crack of the bat that sounds a bit more thunderous than what the A’s had previously heard.

That added muscle came in handy during a nine-inning scrimmage game on Monday. Facing Asian Breeze, a traveling baseball club based out of Arizona, Muncy belted a solo shot to right-center field in his first at-bat.

“That ball carried a little more than usual,” Muncy said, smiling.

Muncy has already been given a nickname in camp. It’s “2.0,” as a play on his shared name with another power-hitting infielder who stars for the Dodgers. His teammates even yelled it out from the dugout as he rounded the bases during that home run trot.

Of course, Muncy realizes there’s a long road ahead before reaching the heights of his All-Star namesake. Sent to the Arizona Complex League upon being drafted last year, he received a primer for the rough transition that exists when elevating from high school to professional ranks.

Muncy struggled in his professional debut, going 4-for-31 (.129) with 12 strikeouts in 11 games. More positive, though, was the experience. The guidance from coaches like former American League Rookie of the Year Bobby Crosby. The extensive work that goes into preparing for an upcoming season. The development of a true pregame routine.

“The coaches did a great job preparing me for this upcoming year on how it’s going to be,” said Muncy. “What it’s like to start playing every day. It was good to face a lot of those high-velocity pitchers every day. Now I’m starting to get a little more adjusted and feeling more confident in my at-bats at the plate.”

The first stop of Muncy’s first full season in the organization will likely come at Low-A Stockton. It’ll provide him the chance to really show off the power the A’s became enamored with when they brought him in for a pre-Draft workout in early 2021. A’s scouting director Eric Kubota recalled Muncy crushing home runs “without a lot of effort” to all parts of the field at the Oakland Coliseum, a stadium long considered to be pitcher friendly.

But what excites Muncy about this upcoming season goes beyond putting up big numbers at the plate or dazzling with his defense at short. It’s the little things, like figuring out how to take care of his body daily. He knows he has the tools to reach the big leagues one day. Now it’s time to learn the intricacies required to reach the game's highest level.

“The main thing this year is to get into next offseason and really know what I need to work on,” said Muncy. “Last year, I had such a small sample size that you don’t know what part of your body needs improvement. The biggest thing this year is to listen to my body, and then next offseason really know if my legs are too tired at the end of the year, or if I had enough juice in the arm. Take notes and figure out what I really need to be prepared.”