The NFL offseason started with a newly signed collective bargaining agreement that was already going to alter how the 2020 season looked before the coronavirus pandemic. More rule changes have adjusted for COVID-19, providing some roster flexibility for teams and some additional security for players. Here's a breakdown of what's changed.

COVID-19 reserve and injured reserve

The Vikings have placed nine players on the NFL's new reserve/COVID-19 list, but the list has been empty since Aug. 13, not counting 12 "false positives" tied to a lab contamination that affected multiple teams last month.

Players will be tested daily, except for game days, throughout the season. Anybody with a positive test or potentially exposed to someone who tested positive is put on the reserve/COVID-19 list.

Symptomatic cases require at least 10 days before returning, and at least three days since the player last had symptoms. Asymptomatic players who test positive can return after five days if testing negative twice. To guard against "false positives," players can be cleared on the same day of a positive test if rerun and point-of-care tests come back negative.

Teams can return an unlimited number of players from injured reserve, and the required stay is only three weeks. Players on IR can return to practice after three weeks but must be activated within the next three weeks.

Roster flexibility

The CBA agreed to in March expanded gameday rosters to 48 from 46, requiring at least eight of the 48 to be offensive linemen. If not, teams can activate 47 on game days. Teams can also now elevate up to two practice squad players for games and effectively have 55 players available, up from 53.

Those practice squad players don't have to be actually signed to the active roster and revert to the practice squad after the game. Players cannot be elevated in consecutive weeks or more than twice without being signed to the active roster.

Not counting against the two-player limit, practice squad players may be elevated up until 90 minutes before kickoff if an active player is placed on reserve/COVID-19 after 3 p.m. the day before a game.

The NFL also expanded practice squads to 16 players from 12 and allowed up to six veterans on practice squads.

Travel rules

All NFL teams have to reduce traveling parties, as the league mandates team buses carry no more than 50% capacity and an open seat between passengers on team planes. Masks are required while traveling. All transportation and hotel staff in contact with the team will undergo COVID-19 screening.

In road cities, a team-only entrance to the hotel will be set up. Players must have their own rooms with no visitors outside of the team. Public or private transportation, dining at restaurants, or using shared hotel facilities such as the gym, are not allowed. Lower-level blocks of rooms are encouraged so players and coaches can use stairs instead of elevators. Prepackaged meals and hand sanitizer will be abundant.

Contingency plans

At the start of Week 1, only six NFL teams plan to host fans, and the Vikings are not among them. Drastic measures for who can be in team facilities or on the sideline during games are aimed at reducing the chances of COVID-19 outbreaks. Cheerleaders, mascots and sideline reporters will not be allowed on the field, and mask wearing is encouraged on the sidelines.

Accrued seasons

For this year, players on Week 1 rosters can now earn an accrued season toward free agency after just one regular-season game; six games are required in a normal season. So entering his contract year, Vikings running back Dalvin Cook can earn a fourth accrued season — and be eligible for unrestricted free agency in 2021 — after Sunday's opener against the Packers.