OAKLAND -- With the A’s reporting to “summer camp” on Thursday and participating in their first workout at the Coliseum on Saturday, the club announced the 60-man player pool, which determines who will be available throughout the 60-game regular season set to begin on July 23 or 24.

The A’s player pool has room for six additions, as Sunday’s announcement listed only 54 players. Among those names are players who were expected to make the roster on Opening Day back in Spring Training along with several top prospects. In all, there are five catchers, 12 infielders, 10 outfielders and 26 pitchers. All of the players on the 40-man roster are in Oakland’s player pool. Nick Allen, Logan Davidson and Daulton Jefferies, all among the A’s top 10 prospects per MLB Pipeline, headline the list of young stars who made the initial list.

The list is down to 53 with the departure of Jorge Mateo, a speedy former top prospect who would have fit perfectly as an extra-innings pinch-runner. He's on his way to the Padres via a pre-Summer Camp trade, however.

• FAQ: Roster and transaction rules for 2020

Prospects in the 60-man player pool will only gain service time if added to the active roster, giving the A’s an opportunity to continue to develop players they don't intend to promote to the big club this season.

The A’s will have two training sites over the next few weeks, one being at the Oakland Coliseum, where most of the players competing to make the Opening Day 30-man roster will train. The other group will be at an alternate site that has not yet been determined by the club. The facility of the Stockton Ports, Oakland’s Class A Advanced affiliate, was the desired location for that alternate camp, though recent COVID-19 restrictions in San Joaquin County may lead to the A’s having to look elsewhere.

The group headed to the alternate site currently stands at 12 players, consisting mostly of prospects like Allen, Davidson and Jefferies. Additions to the A’s player pool will come later in the week and could see other young stars like 2020 first-round pick Tyler Soderstrom, who is expected to officially sign on Monday, according to a report from the San Francisco Chronicle, and No. 4 prospect Robert Puason, the 17-year-old shortstop who was signed last July out of the Dominican Republic.

• FAQ: All you need to know about 2020 season

Catchers (5): Austin Allen, Jonah Heim, Sean Murphy, Carlos Perez, Kyle McCann

Murphy will be the Opening Day starting catcher with the expectation of receiving the bulk of playing time behind the plate this season. At the time Spring Training came to an end, Allen and Heim were entrenched in a close battle for the backup spot. That competition will likely resume once practices get underway in Oakland. Perez is an experienced veteran who brings depth. McCann is the A’s No. 24 prospect and will join other prospects at the alternate site.

Infielders (12): Franklin Barreto, Matt Chapman, Tony Kemp, Vimael Machin, Matt Olson, Chad Pinder, Marcus Semien, Ryan Goins, Sheldon Neuse, Nate Orf, Nick Allen, Logan Davidson

The A’s have three-fourths of their infield set, with Semien, Chapman and Olson making up the strong core that helped lead the club to 97 wins last year. Second base, however, remains wide open. Kemp, Barreto and Machin are all in the running for the spot. The feeling entering Spring Training was that Barreto and Kemp had the inside track on beginning the regular season as a left-right platoon at second base, and neither did anything to sway away from that likelihood.

Machin would provide value in his own way and is likely to begin the season in Oakland with rosters initially expanded to 30 players. Machin may not be flashy, but he has impressed manager Bob Melvin with his approach at the plate. Another plus for Machin has been his ability to play all four infield positions, looking comfortable at each.

Prospects like Allen and Davidson will continue their development at the alternate site, but their chances of making the Major League roster are slim at this point.

Outfielders (10): Seth Brown, Mark Canha, Khris Davis, Robbie Grossman, Ramón Laureano, Stephen Piscotty, Skye Bolt, Greg Deichmann, Dustin Fowler, Buddy Reed

Canha, Davis, Laureano and Piscotty are locks for the Opening Day roster, leaving maybe one or two spots up for grabs depending on how the A’s want to craft their roster.

Starting pitchers (15): Chris Bassitt, Mike Fiers, Jesús Luzardo, Sean Manaea, Frankie Montas, A.J. Puk, Paul Blackburn, Daniel Gossett, Tyler Baum, Parker Dunshee, Grant Holmes, Brian Howard, Daulton Jefferies, James Kaprielian, Daniel Mengden

Luzardo and Puk, the A’s top two pitching prospects who are set to move into the starting rotation, should benefit greatly from the shortened season. Both left-handers were expected to have their innings monitored closely as they’ve yet to complete a Major League equivalent of a full workload. The new 60-game regular season could allow the A’s to maximize their potential. Bassitt is expected to be the long man in the bullpen, though he would be a strong option to join the rotation should the A’s decide to go six deep early on in the season. Montas, Manaea and Fiers will be in the rotation while Mengden could be in the mix for a bullpen role.

Relief Pitchers (11): Jake Diekman, Liam Hendriks, T.J. McFarland, Yusmeiro Petit, Burch Smith, Joakim Soria, Lou Trivino, J.B. Wendelken, Lucas Luetge, Jaime Schultz, Jordan Weems

Hendriks, Petit, Soria, Diekman, Trivino, Wendelken and McFarland should be locks for the Opening Day roster. Smith impressed in Spring Training and could earn a spot in the bullpen with the roster expanded. Luetge, Schultz and Weems will provide depth in camp.