MESA, Ariz. – The A’s had grown accustomed to utilizing Spring Training as a means to get their established core group of players ready for a season. After trading away three of those core players earlier this month, however, it became clear that the club was entering a new chapter.

The departures of Matt Chapman and Matt Olson via trade left wide open vacancies at the corner-infield spots. With a majority of the relievers who made up last season’s bullpen also gone, there's a bevy of pitchers in camp with a real shot at making Oakland’s Opening Day roster.

With several position battles set to unfold in the Cactus League, here’s a look at the positions with the biggest question marks and the players who could fill those roles.

First base

From 2018-21, first base was locked down by Olson, who started 488 games at the position over that time. Seth Brown, who backed up Olson with a handful of games there last season, seems like an ideal replacement. However, A’s manager Mark Kotsay indicated that Brown is being looked at as more of an outfielder to this point. That leaves the competition down to three players in camp as non-roster invitees: Eric Thames, Dalton Kelly and Billy McKinney. McKinney made a strong first impression in his Cactus League debut on Sunday, going 2-for-2 with an impressive two-run homer to left-center.

Middle infield

Elvis Andrus and Tony Kemp are likely the main double-play duo at short and second to begin the season. Not too far behind, though, is Nick Allen, Oakland’s No. 5 prospect per MLB Pipeline. An elite defender at short with Gold Glove potential, Allen has also seen time at second base this spring, which keeps his options open if a spot were to open up.

Third base

Kevin Smith, one of four players acquired in the Chapman deal, was entering camp with Toronto expecting to be in the mix for the third base job with the Blue Jays. That contention now transfers over to the A’s, though his versatility allows him to play all around the infield and even some outfield. Sheldon Neuse, a former top prospect of the A’s, has rejoined the organization this Spring after he was claimed off waivers and is likely Smith’s main competitor for the spot.

Outfield

The A’s will need a new starting center fielder for most of April as Ramón Laureano still has 27 games left to serve on his existing suspension for a performance-enhancing substance. Cristian Pache, acquired from Atlanta in the Olson deal, is a prime candidate to fill that void. Though questions about his bat remain, Pache boasts elite defensive skills that make him a Major League-ready option. There’s also uncertainty with the corner-outfield spots. Left field could see a left-right platoon formed between Brown and Chad Pinder. The A’s might also need Brown or Pinder to shift over to right field, as Stephen Piscotty has been dealing with a shoulder issue in camp and has yet to appear in a Cactus League game. If Piscotty’s injury lingers to the point where he’s not available for Opening Day, the door could open for Skye Bolt or Buddy Reed to nab a spot on the roster.

Starting rotation

Under normal circumstances, Sean Manaea and Frankie Montas would be locked in at the top of the rotation. Of course, the A’s already lost one front-line starter in Chris Bassitt, and now Manaea and Montas continue to have their names floated around in trade rumors. Should they stick around, they'll be established rotation stalwarts, along with left-hander Cole Irvin.

Right-hander James Kaprielian is coming off an impressive rookie campaign and should have a rotation slot, though his status for Opening Day is unclear as he’s currently dealing with AC joint irritation. Brent Honeywell Jr., got the start for the A’s in their Cactus League opener. He along with fellow righty Daulton Jefferies, who has returned to camp fully healthy from a flexor strain, could either be competing for a fifth slot or both get in depending on if the A’s decide to make further transactions involving their current rotation members.

Bullpen

This might be the most active competition in camp with so many spots available. Lou Trivino likely has the closer role. Deolis Guerra and Domingo Acevedo are also returning arms expected to be in the bullpen. Aside from those three, there will be a battle for the other five relief spots.

Left-handed relief options include A.J. Puk, Kirby Snead, Sam Moll and Sam Selmon. Among the right-handed options are Zach Jackson, Dany Jiménez, Justin Grimm, Miguel Romero and Ryan Castellani.