MESA, Ariz. -- Who’s on first? For the first time since 2017, the A’s will have to find a new answer to that question come Opening Day following the deal that sent Matt Olson to Atlanta on Monday.

In the immediate aftermath, manager Mark Kotsay turned to the competitive nature within his locker room.

“We’re looking forward to giving guys opportunities to go over there and earn a job,” Kotsay said Tuesday.

Seth Brown jumps off the page as the primary candidate to take over full-time duties at first base, having spent the vast majority of his time fielding the position in both 2018 with Double-A Midland and ‘19 with Triple-A Las Vegas.

“Obviously, I look for any way that I can help the team, that’s why I’m here,” Brown said. “Those decisions aren’t mine, and to me, I prepare in every way I can to help this team in any way that they need me to help.

“Where I end up playing, is where I end up playing. I prepare myself mentally and physically to fill where I need to fill and to play where I need to play.”

That do-it-all approach resulted in Brown making starts last year at all three outfield positions, designated hitter and first. Moving him out of the outfield could serve to plug one hole, but could also create another defensively -- Brown ranked third on the club in Outs Above Average and was just one of 25 outfielders in the Majors to accumulate at least five OAA in 2021.

If next-day returns are any indication, Brown isn’t permanently trading in his outfield mitt; he took part in an outfielder's drill Tuesday.

After hitting just .191 during the first half last season, Brown found a groove after the All-Star break. Homering 10 times in his final 103 at-bats, the 29-year-old posted an .864 OPS across his last 41 games. The 2021 season finale vs. the Astros marked his first big league multi-homer performance.

“Last year, at the end, I was able to really kind of find that rhythm, and so now it’s just finding that rhythm here in Spring Training and building off of last year,” Brown said.

Never tagged with top-prospect billing, Brown’s ascension from a 19th-round selection out of Lewis-Clark State College in Lewiston, Idaho, to Oakland has been spurred on primarily by his ability to mash every time he’s gotten an opportunity. He earned his first big league callup late in 2019 after hitting 37 homers in 112 games with Las Vegas.

If not Brown, then who? Assuming Oakland doesn’t explore outside assistance, the in-house options remain limited: Eric Thames -- who last appeared in the Majors in 2020 and posted a .617 OPS -- is in camp as a non-roster invitee, while utilityman Chad Pinder has played a total of 16 2/3 innings at first (and two starts there) during his six-year career. In their pipeline, the A’s have just one prospect ranked inside their top 30 who has seen consistent time at first: No. 29 prospect Lawrence Butler, who hasn’t played above High-A, where he’s played 14 games.

While the Olson deal opens the possibility for new opportunities for myriad players, his presence figures to continue to resonate.

“I’m obviously so happy for [Olson],” Brown said. “Gets to go home; obviously sorry to see him go. We’re going to miss him. But it’s just the way the game is and you’re excited for any one of your buddies that gets an opportunity to go play.”

Olson’s departure figures to have a trickle-down effect not just positionally, but also on the A’s lineup. It’s difficult to replace the 74 extra-base hits, 111 RBIs and .371 on-base percentage that he compiled en route to an eighth-place finish in American League MVP voting last year, after all.

“As an offense, [we’ll] find our identity here through the next 18 games and I think there’s enough talent in that room that we’ll be fine,” Kotsay said.

“To me, especially with the last few years being crazy, with everything that’s been affecting the game, the world, all that stuff -- you just got to find those routines that are going to keep you where you need to be,” Brown said. “So nothing really changed for me. … [I’m] ready to go.

“I’m prepared for anywhere they need me.”