If you've followed baseball closely over the years, you should have a basic understanding of a franchise's various rosters and how they differ.
There's the 25-man roster, of course, the group of players actively in the major leagues at any given moment. Then there's the 40-man roster, which in addition to the 25 active big leaguers includes players on the short-term injured list (10-day IL) and the group of top-tier minor leaguers who are most likely to be promoted at some point. Players recovering from major injuries (60-day IL) don't count, nor do the majority of minor leaguers who fill out the rosters throughout the farm system.
We're all going to have to familiarize ourselves with an entirely new set of rosters this season, though. The 2020 season is going to be different from anything we've ever experienced, and that includes the various rosters now in effect.
There's still the active big league roster, but it will include 30 players on opening day to account for the lack of time pitchers will have to build their arms up during the upcoming and abbreviated summer training. Teams will be required to pare that 30-man active roster down to 28 after two weeks of play have been completed, then down to 26 two weeks after that. The roster will remain at 26 the rest of the season, with no extra September call-ups this year.
And the 40-man roster still exists, though only as the means for identifying which players can be called up to the majors along the way. As always, if a team wants to promote somebody not on the 40-man roster, it will have to clear a spot either by releasing someone else or placing a player on the 60-day IL.
But with no minor leagues in 2020, where will those potential call-ups be? The answer: in a separate facility near teams' home ballparks where they can work out daily and even hold scrimmages to keep guys fresh in case they're needed. (On top of that, teams will be allowed to bring three extra players with them on the road, a taxi squad of guys who would be the most likely players promoted in case of an injury.)
Who's going to be participating in that backup camp, staying fresh in relative obscurity while the big leaguers commence with this most unusual season? We got our first glimpse of the possibilities Sunday when all Major League Baseball clubs were required to submit their 60-player pool to league offices.
Yes, the key number this year is 60. Anyone who isn't on the active roster or three-man traveling taxi squad will be sequestered at the backup camp, which the Nationals are hoping to hold at the new Single-A facility in Fredericksburg (though that has not yet been finalized).
That 60-man roster essentially represents the pool of players who could appear in the majors for the Nationals in 2020 - with some caveats, of course.
Trades are still allowed up until Aug. 31, so players from other organizations could be acquired until then. Free agents could be signed as well, and there remain a good number of unemployed veterans out there who could help a team in need along the way.
The Nationals' 60-man roster also could lose a couple of players before camp opens Friday, if anyone elects to opt out for health reasons. Ryan Zimmerman, with a newborn son at home and a close relative (his mother, Cheryl) with a major illness (multiple sclerosis) that makes her a higher risk to develop serious problems if she contracts COVID-19, already has publicly admitted he may opt out. Zimmerman and any other players considering it will need to make their official decisions soon, and that could open up more roster spots.
What to make of the Nationals' choices to fill out the current 60-man roster? Beyond the obvious members of the opening day roster, players tend to fit into one of three categories ...
* Members of the 40-man roster who would normally move back and forth between the majors and Triple-A. That includes players like outfielder Andrew Stevenson, infielder Wilmer Difo, catchers Tres Barrera and Raudy Read, and pitchers Aaron Barrett, James Bourque, Erick Fedde, Kyle Finnegan, Ryne Harper, Kyle McGowin and Austen Williams.
* Veterans who were at spring training as non-roster invitees. That includes guys like utilitymen Emilio BonÃfacio and Brandon Snyder, catcher Welington Castillo, and pitchers Fernando Abad, Sam Freeman, Javy Guerra and Kevin Quackenbush.
* Young prospects who realistically aren't part of the team's 2020 plans but will now have an opportunity to work in a semi-formal setting for the next three months to make up for their lost minor league seasons. That includes players like infielder Luis GarcÃa, catcher Jakson Reetz, and pitchers Tim Cate, Seth Romero and Jackson Rutledge.
How many of these guys will actually appear in a big league game for the Nationals this season? It's hard to guess how much roster maneuvering there will be in this unprecedented season, but for comparison's sake: The Nats used 50 total players last season while playing 162 games, and they've never used more than 57 players in any individual season.
It seems unlikely they'd top the 40 mark during this 60-game season. But as with so much else right now, it's impossible to predict how a season none of us has ever experienced will play out.