Nationals have few decisions for NLDS roster

WASHINGTON -- When manager Dusty Baker, general manager Mike Rizzo and the rest of the Nationals' brass sit down this week to determine the team's National League Division Series roster, most decisions will have been made for them. Between the everyday players, bench stalwarts, starting pitchers and key relievers, most of the team that will face the Dodgers starting with Game 1 on Friday (FS1, 5:30 p.m. ET/2:30 p.m. PT) is already set.
Here are the players who will almost certainly make up Washington's 25-player group:
Catchers (2):Jose Lobaton, Pedro Severino
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Infielders (6):Ryan Zimmerman, Daniel Murphy, Danny Espinosa, Anthony Rendon, Clint Robinson, Stephen Drew
Outfielders (4):Jayson Werth, Trea Turner, Bryce Harper, Chris Heisey
Starting pitchers (4):Max Scherzer, Tanner Roark, Gio González, Joe Ross

Relief pitchers (5):Mark Melancon, Shawn Kelley, Blake Treinen, Marc Rzepczynski, Sammy Solís.
That adds up to 21 players, leaving four spots up for grabs.
"We're trying to determine, trying to get this roster ready," Baker said on Tuesday. "I don't think any roster is like completely the way you want it, but we're gonna try to get it as close as we can to fill as many holes or possibilities as we can."
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Here are the questions that will determine the Nationals' final roster:
1. How many relief pitchers will they carry?
In a five-game series, many teams can get away with only seven relievers. But with Gonzalez inconsistent and Ross not fully stretched out after a shoulder injury, the Nationals will likely roster eight bullpen arms. That means righty Matt Belisle should be on the roster, at the expense of infielder Wilmer Difo.
2. How many of those relievers will be lefties? Who will they be?
The Nationals have carried at least three left-handers for most of the season, and it's a safe bet they will continue to do the same in the NLDS, against the left-handed-hitting-heavy Dodgers.
Assuming Rzepczynski and Solis make the roster, the third spot comes down to Oliver Pérez and Sean Burnett. Since Perez has been with the team all season and has pitched in high-leverage spots recently, expect him to make the team.
3. Who will be the long reliever?
This likely comes down to Yusmeiro Petit and Reynaldo López, a veteran who gets by on guile vs. a rookie with electric stuff. Baker has talked about both as if they'll be on the roster, but there likely won't be enough room, unless Belisle stays home.
This one could go either way, but the veteran Petit could have a slight edge, due to his postseason experience.
4. Who will be the fifth outfielder?
With Michael Taylor nursing a thumb injury, this decision will be between Ben Revere, who entered the season as a starter but never got going, and Brian Goodwin, who was called up in August and hit a solid .286/.318/.429 in 44 plate appearances.
If this was based on hitting alone, maybe Goodwin would get the nod. But this team needs a contingency plan in center field and a pinch-running option off the bench, and Revere fills both roles. For a fifth outfielder, Revere's speed and defense will likely outweigh Goodwin's extra pop.