As the NFL approaches the 2021 season, the league informed clubs that it would not extend the season to accommodate a COVID-19 outbreak among unvaccinated players that causes a game cancellation.

NFL Network's Tom Pelissero reported Thursday that the NFL sent a memo to its clubs stating that if a game cannot be rescheduled during the 18-week schedule due to a COVID-19 outbreak among unvaccinated players, the team with the outbreak will forfeit and be credited with a loss, per sources informed of the situation.

In addition, players on both teams will not be paid for the lost contest, and the team responsible for the cancelled game due to unvaccinated players will cover financial losses and be subject to potential discipline from the Commissioner's office.

Last year, the NFL bent over backwards to rework the schedule on the fly as outbreaks occurred. Zero games were missed over 17 weeks.

In 2021, the NFL plans to play its 272-game slate over 18 weeks.

"We do not anticipate adding a '19th week' to accommodate games that cannot be rescheduled within the current 18 weeks of the regular season," the memo stated in a highlighted portion.

It's the clearest line the NFL has drawn to date and the most substantial incentive yet for owners, teams and coaches to pressure players to get vaccinated. The league has insisted it will not mandate vaccinations, but the restrictions in place for non-vaccinated players and potential penalties to teams make the NFL's stance crystal clear.

Thursday's memo underlines that in green. Money green.

"If a game is cancelled/postponed because a club cannot play due to a Covid spike among or resulting from its non-vaccinated players/staff, then the burden of the cancellation or delay will fall on the club experiencing the Covid infection," the memo states. "We will seek to minimize the burden on the opposing club or clubs. If a club cannot play due to a Covid spike in vaccinated individuals, we will attempt to minimize the competitive and economic burden on both participating teams."

It's the clearest language the league has used in delineating the difference between outbreaks among vaccinated individuals and those who elect not to be vaccinated.

NFL Network's Judy Battista reported that with players beginning to report for camps, progress on vaccinations has increased. More than 78 percent of players league-wide have had at least one shot, and 14 clubs have at least 85 percent of players vaccinated. Pelissero reported that all 32 teams have at least a 50 percent vaccination rate among players.

"We're pleased with those numbers, but we're not satisfied. We want to see them continue to go up," NFL chief medical officer Dr. Allen Sills told Battista on Thursday's NFL NOW. "Certainly those rates are well above what we're seeing in the rest of society and certainly above the same age group as most of our players are. So a great head-start, more work to be done."

According to Thursday's memo, vaccinated players or staff who test positive and are asymptomatic can return to duty after two negative tests 24 hours apart. For non-vaccinated persons who test positive, the 2020 protocols remain in place, requiring a 10-day isolation.

In essence, the NFL is telling its clubs to up their efforts to convince players to get vaccinated. Otherwise, the burden of risk falls on the team should an outbreak occur.

Pelissero shared an NFLPA email sent to players Thursday night in which clubs were reminded that the "same basic rules" also applied last year, citing that players wouldn't have been paid for games if there was a COVID-19 outbreak and all previously agreed upon joint protocols are effective, when followed as the 2020 season proved.

The NFLPA did note one small difference in that the NFL decided to impose additional penalties on teams which are responsible for an outbreak, should one occur, and the availability of vaccines.

The memo in full resides below:

This will summarize key operating principles relating to addressing the continuing Covid-19 threat for the 2021 season. We will review these principles and related matters on the 32-club call this evening. These principles are based on last season's experience and follow discussions that we have had with a number of league committees, medical experts, outside advisors, and many of you. As we learned last year, we can play a full season if we maintain a firm commitment to adhering to our health and safety protocols and to making needed adjustments in response to changing conditions.

These operating principles are designed to allow us to play a full season in a safe and responsible way and address possible competitive or financial issues fairly. While there is no question that health conditions have improved from last year, we cannot be complacent or simply assume that we will be able to play without interruption - either due to Covid outbreaks among our clubs or outbreaks that occur within the larger community. These principles are intended to help inform decisions, recognizing that, as in 2020, we will need to remain flexible and adapt to possibly changing conditions.

Medical Principles

• We will maintain our focus on health and safety, with the well-being of everyone associated with our game remaining our highest priority.

• Nearly all clubs have vaccinated 100 percent of their Tier 1 and 2 staffs. Clubs have put appropriate protocols in place for the relatively few staff who have not been vaccinated, consistent with the guidance given last April. As of today, more than 75 percent of players are in the process of being vaccinated, and more than half the clubs have vaccination rates greater than 80 percent of their players.

• We know that vaccines are safe and effective and are the best step anyone can take to be safe from the coronavirus. The vaccines continue to provide strong immunity against variants of the coronavirus, including the Delta variant. Even with recent increases, new cases remain far below the peak levels of earlier this year. Both the CDC and major hospital systems throughout the country have reported that 97 percent or more of the new cases and virtually all hospitalizations are seen in unvaccinated individuals. While there have been "breakthrough" infections - cases where a vaccinated individual has been infected - those cases tend to be mild and people recover from the infection relatively quickly.

• If a vaccinated person tests positive and is asymptomatic, he or she will be isolated and contact tracing will promptly occur. The positive individual will be permitted to return to duty after two negative tests at least 24-hours apart and will thereafter be tested every two weeks or as directed by the medical staffs. Vaccinated individuals will not be subject to quarantine as a result of close contact with an infected person.

• If an unvaccinated person tests positive, the protocols from 2020 will remain in effect. The person will be isolated for a period of 10 days and will then be permitted to return to duty if asymptomatic. Unvaccinated individuals will continue to be subject to a five-day quarantine period if they have close contact with an infected individual.

• Persons who had a previous Covid infection will be considered fully vaccinated 14 days after they have had at least one dose of an approved vaccine.

• We will remain in close contact with medical and public health authorities at all levels of government, as well as with our own medical advisors and the NFLPA, and will communicate any changes in medical or public health advice promptly.

Competitive Principles

• The league will make every reasonable effort, consistent with underlying health and safety principles, to complete the full 272-game regular season within the current 18 weeks and all postseason games as scheduled, in a safe and responsible way. This is grounded in a commitment to players, coaches, fans, and business partners. We do not anticipate adding a "19th week" to accommodate games that cannot be rescheduled within the current 18 weeks of the regular season.

• Every club is obligated under the Constitution and Bylaws to have its team ready to play at the scheduled time and place. A failure to do so is deemed conduct detrimental. There is no right to postpone a game. Postponements will only occur if required by government authorities, medical experts, or at the Commissioner's discretion.

• In light of the substantial roster flexibility in place for the 2021 season, absent medical considerations or government directives, games will not be postponed or rescheduled simply to avoid roster issues caused by injury or illness affecting multiple players, even within a position group.

• If a game is cancelled/postponed because a club cannot play due to a Covid spike among or resulting from its non-vaccinated players/staff, then the burden of the cancellation or delay will fall on the club experiencing the Covid infection. We will seek to minimize the burden on the opposing club or clubs. If a club cannot play due to a Covid spike in vaccinated individuals, we will attempt to minimize the competitive and economic burden on both participating teams.

• Whether to reschedule a postponed game will be dependent on health and safety reasons at the recommendation of medical experts as well as considerations of stadium availability, schedule integrity, fan convenience, and other appropriate matters.

• If a game cannot be rescheduled within the current 18-week schedule and is cancelled due to a Covid outbreak among non-vaccinated players on one of the competing teams, the club with the outbreak will forfeit the contest and will be deemed to have played 16 games for purposes of draft, waiver priority, etc. For the purposes of playoff seeding, the forfeiting team will be credited with a loss and the other team will be credited with a win.

Financial Principles

• If a game is rescheduled due to a Covid outbreak among unvaccinated players on one of the competing teams, the club experiencing the outbreak will be responsible for all additional expenses incurred by the opposing team and will also be required to pay any shortfall between actual and expected payment to the VTS pool.

• If a game cannot be rescheduled within the current 18-week schedule and is cancelled due to a Covid outbreak among unvaccinated players on one of the competing teams, that club will forfeit the contest and will be responsible for the lost payment to the VTS pool.

• If a game is cancelled and cannot be rescheduled within the current 18-week schedule due to a Covid outbreak, neither team's players will receive their weekly paragraph 5 salary.

If a game is cancelled because of a Covid outbreak among unvaccinated players/staff, in addition to the financial penalties identified above, the Commissioner retains the authority to impose additional sanctions, particularly if the Covid outbreak is reasonably determined to be the result of a failure by club personnel to follow applicable protocols.

• Costs of testing players and staff for Covid-19 during the 2021 season will be paid for as follows: the first $400,000 of each club's actual testing costs will be treated as a league expense. Each club will pay its own actual testing costs as they are incurred and will then be reimbursed after the season for up to $400,000 in actual testing costs. All testing costs in excess of $400,000 will be the responsibility of the club. Eligibility for this reimbursement will depend on full compliance with all Covid-19 related testing protocols in effect for the 2021 season. Any material deviation may result in a club being ineligible for reimbursement, in addition to any other consequences.