OAKLAND -- One of the more successful clubs in baseball over the past few years, the A’s now face one of their stiffest challenges in recent memory.

After building a squad that has helped push them to postseason appearances in each of the past three seasons, free agency could deliver a huge blow to the A’s, whose 10 free agents entering the offseason were tied for the most in the Majors. Among those players now on the open market are shortstop Marcus Semien and All-Star closer Liam Hendriks.

While Oakland remains hopeful of bringing some of its key players back, retaining big names like Semien and Hendriks -- both of whom are considered to be at the top of this free-agent class -- appears to be a long shot. But no matter which players are back, the A’s always seem to find a way to piece together a club that ends up in contention for the postseason.

With a solid young core still intact, with players such as Matt Chapman, Matt Olson, Ramón Laureano, Jesús Luzardo and Frankie Montas, the expectation is that A’s executive vice president of baseball operations Billy Beane will work his magic yet again to keep this team on the right track.

“There may be some interesting pickups later on,” A’s manager Bob Melvin said. “It’s not ideal. We’ve had great contributions from our free agents. But again, we have a group of guys here that we feel really good about.”

With the calendar set to flip to 2021, here are five questions surrounding the A’s as they enter the new year.

1. Will Semien be playing elsewhere?
Though Semien did not begin his career with the A’s, it feels as if he’s a homegrown talent. Since joining Oakland in 2015, the shortstop has blossomed into a team leader and one of the best players at his position, earning a third-place finish in American League MVP Award voting in '19.

Semien’s value to the club goes beyond his production on the field. As the longest-tenured A’s player, Semien has helped mold the winning atmosphere among the team’s younger players, and his strong work ethic has rubbed off on stars like Chapman and Olson. The Bay Area native has also been involved in numerous community programs in Oakland. So if Semien goes elsewhere, that loss is felt in more ways than one.

2. What is A.J. Puk’s long-term role?
The A’s had visions of a dynamic rookie duo of Luzardo and Puk making an impact in their rotation this past season. But while Luzardo graduated to the big leagues on a full-time basis and impressed, Puk, Oakland’s No. 1 prospect per MLB Pipeline, was shelved for the whole season and underwent left shoulder surgery in September.

Puk is expected to make a full recovery and be ready to go at full strength by Spring Training. While the front office maintains that Puk is still being considered for a starting role, it might make more sense for the electric left-hander to pitch out of the bullpen, given his arm injuries over the past few years.

Puk already has experience pitching in relief, having made a brief cameo out of the bullpen in 2019, and his premium stuff could make him a strong candidate to take over as closer, should Hendriks leave in free agency. When asked about Puk’s prognosis for the 2021 season, Melvin left the door open for a potential relief role.

“Where we use A.J., we’ll see,” Melvin said. “I think right now, the thought is to build him up as a starter, but he could be a bullpen piece for us as well if we feel we’re a little short in the bullpen.”

3. Are the young starters ready for the Majors?
The A’s already lost Mike Minor to the Royals in free agency, and there hasn’t been much talk of them reuniting with free-agent righty Mike Fiers. The reason for this is that Oakland possesses a group of young pitching prospects who appear to be Major League-ready.

Daulton Jefferies (the club's No. 7 prospect) and James Kaprielian (No. 12) each had brief stints with the A's this past season, while Grant Holmes (No. 16) was one of the more impressive arms at the club’s alternate training site in San Jose during the summer. With an expected opening in the A’s starting rotation and Puk possibly looking at a bullpen role, the door will be open for one of these prospects to take advantage and secure a role in Oakland.

4. Who is the closer in 2021?
Hendriks seems the least likely free agent to re-sign with the A’s, given the large interest he’s already garnering from several teams, so it will likely become a matter of where his replacement comes from. Oakland could look to the free-agent market for a veteran, perhaps one of its current free agents like Yusmeiro Petit or Joakim Soria.

Expect the A’s to also inquire about relievers on the trading block. If not, left-hander Jake Diekman appears to be the leading candidate to take over as closer, with right-handers Lou Trivino and J.B. Wendelken also in the mix.

5. How does the AL West look in 2021?
The A’s aren’t the only club in their division facing some serious losses in free agency. The Astros stand to lose star outfielders Michael Brantley and George Springer on the open market. In a sign of a likely rebuild, the Rangers traded away ace starter Lance Lynn this offseason. The Angels and Mariners have made minor moves to this point, but they still have major holes to fill as well.

So regardless of who the A’s bring back in free agency, it’s important to also remember they still likely possess the deepest all-around roster in the AL West at this point, with several key pieces from last season's division-winning team still in the fold.