NFL Players Association team player representatives are scheduled to convene on a conference call Friday morning as the players work to finalize an agreement with team owners on the rules and finances of the 2020 NFL season, according to sources.

The sources said the two sides were still negotiating Thursday night on at least three key points:

• Rules for the training camp acclimation period.

• Procedures via which players could opt out of the season for coronavirus-related reasons and what would happen to the contracts of those who do.

• How to handle the league's long-term finances and salary caps of future years in the wake of projected 2020 revenue loss as a result of the coronavirus pandemic.

Sources on both sides of the talks said the hope was to get everything wrapped up by the time teams report to camp. With Houston Texans and Kansas City Chiefs players scheduled to report this weekend and begin COVID-19 testing, the window for accomplishing that is growing smaller, but Thursday night's round of talks ended with optimism that a deal could be completed within the next couple of days, sources said.

The biggest issue of the three listed above appears to be the last one. NFL team owners are projecting a significant amount of lost revenue this season as a result of having to play games in empty or partially filled stadiums. Estimates of those losses vary, but most expectations peg the amount to be between $3 billion and $4 billion, which would represent about 20-25% of league revenue for the year. And, of course, those losses would be higher if games had to be canceled.

Since the salary cap is tied to league revenue, a loss in revenue probably would mean a reduction of next year's cap. Sources say the owners' initial proposal was to absorb the cap hit this year and next -- holding a percentage of the players' 2020 income in escrow and reducing next year's salary cap in accordance with the losses. This year's salary cap is $198.2 million per team. If revenue-loss projections are accurate and no other action is taken, next year's cap could drop into the range of $120 million to $130 million per team.

This would make things very difficult for a number of teams and probably would result in a large number of players being released or having their salaries reduced by teams trying to get under the drastically reduced cap. For that reason, the players' initial proposal was to smooth out the cap reductions over the life of the new collective bargaining agreement, which runs through the 2030 season. As a (very) rough example, as opposed to knocking $70 million off of next year's cap, it would divide $70 million by 10 and apply a $7 million reduction per year through the end of the CBA.

Sources said there was movement on this Thursday night and that the likely outcome is a compromise that smooths the hit out over five years, from 2021 to 2025. One source said the current discussions revolve around a salary-cap minimum in the affected years. (Example: If the projected losses would drop the 2021 cap to $130 million but the agreed-upon "floor" for 2021 was $160 million, the cap would be set at $160 million and the other $30 million would have to be made up in similar fashion in future years. If the revenue projections came in higher than expected, the caps in future years could be adjusted upward accordingly. There is optimism among owners and players that the contract extensions the league plans to do with its TV network partners in the next year or two will lead to significant cap growth.)

As for the other two issues -- the opt-out procedures/payments and the training camp acclimation period -- sources say they remain tied up with the long-term financial piece of the negotiations. It's possible one side could concede on one of those issues in exchange for a concession on the salary-cap discussions.

Earlier this week, owners proposed a training camp acclimation period that was closer to what the players have asked for. The players want to start camp with 21 days of just strength and conditioning workouts, followed by 10 days of practice without pads, followed by a 14-day contact acclimation period in which padded practices would be permitted.

As for opt-outs, players were told in a conference call earlier this week about a proposal that would pay $250,000 stipends to active-roster players (and $100,000 stipends for practice squad players) who opted out because they were in one of the defined high-risk COVID-19 groups (such as BMI over 28, or sleep apnea, for example).

As of Thursday night, sources said, the owners' latest proposal included opt-out provisions for high-risk players as well as for non-high-risk players, but with different and varied rules and compensation for the two groups.

But players want better protections and answers on what happens to their salaries if they begin the season but can't finish it. Those issues are still being negotiated along with the bigger-picture financial concerns.

Tuesday is the report date for all teams except for Houston and Kansas City (who report earlier because they're scheduled to play the Thursday night opener). Under the COVID-19 testing protocols announced earlier this week, players will be tested on their first day, quarantine at home for the next two days, be tested again on Day 4 and then be allowed into the facility for their training camp physicals on Day 5 only if both of their tests come back negative. Players will be tested every day for the first two weeks of camp, then every other day after that as long as their team's positive test rate is below 5%.