Team facilities will be closed to all in-person activities Monday and Tuesday, the NFL said Friday in a leaguewide memo.
The ban does not apply to teams scheduled to play on Monday or Tuesday.
The NFL cited the spike in coronavirus cases around the country as well as the "understanding that a number of players and staff celebrated the Thanksgiving holiday with out-of-town guests" as reasons for closing facilities.
All activities will be conducted virtually except essential medical treatment and rehab, according to the memo.
The NFL Players Association also instructed players to alert teams if they had guests over the past several days for the purposes of additional testing when facilities reopen.