NFL owners and players are holding separate meetings this week regarding the status of the league's collective bargaining negotiations, and those meetings could result in votes to approve or reject the current CBA proposal, sources close to the negotiations told ESPN.

Sources said that both sides are working to reach a decision by the March 18 start of the 2020 league year, but it remains unclear whether the two sides can reach an agreement by then -- or at all. One source close to the negotiations described them Wednesday night as "on a knife's edge."

All 32 NFL owners are scheduled to meet Thursday in New York City for an update on the current proposal, and sources said they could vote on whether to move ahead with it. Three-fourths of the league's owners have to approve the CBA for it to be ratified. The Thursday meeting was scheduled Wednesday.

But the players have to vote, too, and it's unclear whether they'll do that this week. National Football League Players Association team player reps and the NFLPA's executive council, which had been planning a Friday meeting in Washington, D.C., on the topic, are now planning to hold a conference call Friday instead of meeting face-to-face. That call could result in a vote on whether to approve the current offer or reject it.

If two-thirds of the NFLPA's player reps approve the deal, it would move on to the next stage, in which all NFL players would vote and a simple majority would be required to approve. If there aren't enough votes among the player reps to approve the deal Friday, sources told ESPN, there's a chance that the current proposal will stall and negotiations won't pick up again until next offseason, increasing the chances of an NFL work stoppage in 2021. The current CBA, which began in 2011, expires in March 2021.

The current proposal would allow the league to expand the regular season from 16 games to 17 games at some point in the next four years (though no sooner than 2021) in exchange for financial and other concessions the players have sought in negotiations. One concession is that the preseason will be shortened to three games per team, sources said. ‬

The league's desire to expand the regular season from 16 games to 17 games has been met with harsh opposition from many players, who view an expanded season as an unnecessary increase in the risk to players' health and safety. As a result, a deal that looked bound for ratification as recently as two months ago has encountered some peril with less than a month to go before the start of the 2020 league year. Union leaders have touted to players the benefits of the proposed new deal, which includes a higher percentage of league revenue going to players, improvements in the drug policy and discipline policy, higher minimum salaries, higher per-team spending floors and relaxed offseason work rules.

One of the concessions players have been seeking since CBA talks began last year is an increase in the minimum salary, which applies to a significant chunk of the league's population. Under the proposed new CBA, sources told ESPN, NFL minimum salaries would rise by roughly 25%. For example, the minimum salary for rookies in 2020 was scheduled to be $510,000. Under the new CBA, which would begin in 2020 and run through 2029, that figure would rise to $640,000. The minimum for players with one year of experience would jump from $585,000 to around $730,000, and so on up to the 10-year veteran minimum, which is scheduled to be $1.045 million in 2020 and would rise to roughly $1.3 million.

Sources said the players who are opposed to a 17-game season have pushed back and asked the union to demand further concessions from owners, particularly in the area of offseason and training camp work rules.

The NFLPA held a series of conference calls Thursday and Friday to which all players were invited. The purpose of those calls was to help determine what additional concessions players would need to secure from the league's side if they were to agree to a 17-game season. Following those calls, the union discussed counterproposal ideas with the league, and one source said the proposal has been altered to reflect the changes the players sought, though work remains to be done on a couple of issues, including training camp rules and the "fully funded rule" that players and their agents loathe because teams use it as an excuse to not guarantee contracts.

If this week's discussions with the owners have improved the offer sufficiently in the eyes of the players, there could soon be a series of votes to move the negotiations along to the approval stage. If not, CBA negotiations might have reached an impasse.