The Giants played the final month of the regular season with 28 players, but they’ll have to pare that number down to 26 when they set their roster to face the rival Dodgers in the National League Division Series beginning tonight.

San Francisco took advantage of its depth by frequently shuttling players on and off its roster during the regular season, but it won’t have that flexibility during the playoffs. Clubs must set their teams before each round and can only replace players in the event of an injury.

Here’s a look at how the Giants’ postseason roster is shaping up and some of the tough decisions that loom:

Catcher

Locks (2): Buster Posey, Curt Casali

Possibilities (1): Joey Bart

The Giants will have Bart ready to step in if necessary, but barring an injury, they’ll continue to lean on the veteran tandem of Posey and Casali. The Giants carefully monitored Posey’s workload during the season, but there’s a good chance the 34-year-old veteran will start every game during the postseason if his body allows it.

Infield
Locks (6): Brandon Crawford, Tommy La Stella, Donovan Solano, Wilmer Flores, Evan Longoria, Darin Ruf

Possibilities (2): Thairo Estrada, Jason Vosler

Brandon Belt isn’t expected to be available in the NLDS due to a left thumb fracture, but the Giants should be able to cover first base through some combination of Ruf, Flores and LaMonte Wade Jr. Not carrying Estrada would be tough and leave the Giants without a true backup shortstop, but Crawford -- the club’s leading MVP candidate -- has been a workhorse on the infield this season.

Outfield
Locks (3): Mike Yastrzemski, LaMonte Wade Jr., Austin Slater

Possibilities (2): Steven Duggar, Alex Dickerson

Given their depth, the Giants could have a difficult time deciding whether to carry 13 position players and 13 pitchers, or go with 14 position players and 12 pitchers. If they opt to carry an extra reliever, a role player like Duggar or Dickerson could end up being the odd man out. Duggar offers elite defense and speed, so he’d likely have a leg up over Dickerson, who went 1-for-6 with a walk over five games after returning from a hamstring injury.

Utility
Locks (1): Kris Bryant

Possibilities (1): Mauricio Dubón

Dubón hit .332 with a .908 OPS and eight home runs over 63 games after being demoted to Triple-A Sacramento, but he doesn’t have a clear path to the postseason roster right now given the emergence of players like Estrada and Duggar.

Rotation
Locks (4): Kevin Gausman, Logan Webb, Alex Wood, Anthony DeSclafani

Possibilities (1): Johnny Cueto

Cueto missed most of September with a right elbow injury, but he recovered in time to be activated for the final weekend of the regular season. He returned to an entirely new role, though, as he was asked to shift to the bullpen for the first time in his 14-year career. Cueto accepted the assignment, but he expressed a bit of trepidation about making the adjustment and gave up one run over 2 1/3 innings in his first career relief appearance against the D-backs on Thursday.

The Giants won’t need five starters in the NLDS, and they have no shortage of quality relief options, but few of their pitchers can match the postseason experience of Cueto, who won a World Series with the Royals in 2015 and tends to shine when the lights are brightest. The 35-year-old veteran will also be hoping for a chance to audition for a new contract, as the Giants are likely to decline his $22 million team option for 2022 this offseason.

Bullpen
Locks (6): Jake McGee, Camilo Doval, Tyler Rogers, Jarlín García, Dominic Leone, José Álvarez

Possibilities (6): Zack Littell, Kervin Castro, Jay Jackson, Sammy Long, Caleb Baragar, John Brebbia

Doval’s dominance down the stretch proved to be a notable development for the Giants, who began to trust the 24-year-old flamethrower to close games while McGee was on the injured list. It remains to be seen whether Doval will remain the closer in the playoffs, but he’s poised to pitch big innings due to his electric stuff and calm demeanor on the mound. Castro, another rookie, also impressed, though he hasn’t been used in as many high-leverage spots and stumbled a bit in his final regular-season outing against the Padres on Sunday, so his standing is a bit more uncertain.

The injuries to Tony Watson (left shoulder strain) and Scott Kazmir (right hamstring strain) and the decision to designate José Quintana for assignment thinned the Giants’ relief depth from the left side, but they still have three other trusted southpaws -- McGee, García and Álvarez -- and could consider adding Baragar or Long to the mix if they feel they need one more lefty option heading into the NLDS.