Of the various agreements that the NFL and NFL Players Association need to reach before training camps can open, one relates to how many players will be present when training camps open.
As previously explained, the NFLPA wants the 90-man roster to be reduced to 80 for training camp in a pandemic. A league source has explained to PFT that the 80-man roster request comes from NFLPA leadership, and that the rank-and-file prefers to have 90 players.
Beyond the obvious fact that 320 players would lose their jobs without even having a chance to win roster spots, players who have been around the block one or twice or more realize that a certain number of bodies are needed in order to properly get through practice, so that everyone can get the preparation they need. Drop 10 players, and some of the other players who remain will end up putting in more work to run routes or throw passes or otherwise take reps aimed at allowing others to get their reps in.
Per the source, the league office has no real objection to slashing the rosters to 80. Some teams already were thinking about doing that in order to better manage the coronavirus protocol. Many teams, however, want to bring 90 players to camp -- especially since there will be an inevitable thinning of the herd as players test positive.