The NBA and the National Basketball Players Association came to an agreement Sunday night on rules allowing additional replacement players for teams dealing with players entering the league's health and safety protocols, according to a memo obtained by ESPN's Adrian Wojnarowski.

The amended rules, which were outlined in the memo, went into effect Sunday night and will remain in place until Jan. 19 -- at which time the league will give teams further guidance on how things will proceed from there.

Under the agreement, teams will be allowed to sign a replacement player for each positive COVID-19 case that crops up across its roster. So if a team has five positive cases of COVID-19, for example, it could sign five replacement players.

Meanwhile, teams will have to sign at least one replacement player if they have two positive COVID-19 cases; at least two if they have three positive COVID-19 cases; and at least three if they have four or more positive COVID-19 cases.

The memo also states that any time a team is required to sign a player, that player must be available by the start of the team's first game after the allowance to sign a replacement player is granted by the NBA.

Any replacement players who are signed also won't count toward a team's yearly salary, and also will not add to its potential luxury tax payment. That is a significant difference for a team like the Brooklyn Nets, which is among the teams currently dealing with a significant COVID-19 outbreak and had Sunday's game against the Denver Nuggets, as well as Tuesday's game against the Washington Wizards, postponed. According to ESPN's Bobby Marks, each replacement player the Nets needed to sign, if his salary counted toward the luxury tax, would cost them roughly $500,000.

As part of the agreement, the NBA and the NBPA also agreed to scrap the limit on the number of games a two-way player is allowed to be on a team's active roster. Under a previous agreement the two sides came to this summer, there had been a 50-game limit. Now, that limit no longer exists, with players getting paid an amended rate if they wind up being active for more than 50 games this season.

The NBA postponed five games Sunday -- three games that were scheduled to be played Sunday (New Orleans Pelicans-Philadelphia 76ers, Cleveland Cavaliers-Atlanta Hawks and Nuggets-Nets) as well as Monday's Orlando Magic-Toronto Raptors game and Tuesday's Wizards-Nets game -- as a result of the spike in positive COVID-19 cases sweeping through the league over the past week.

Dozens of players have entered the health and safety protocols this past week, including stars such as Brooklyn's Kevin Durant, James Harden and Kyrie Irving, Milwaukee Bucks forward Giannis Antetokounmpo and Hawks guard Trae Young, as well as Los Angeles Lakers coach Frank Vogel.

The first team with a significant outbreak this season, the Chicago Bulls, returned to action Sunday night for the first time since its games Tuesday against the Detroit Pistons and Thursday against the Raptors were postponed -- the first postponements by the NBA this season. The Bulls beat the Lakers 115-110 in Chicago.

As positive cases mounted across the league, teams scrambled to fill out their rosters with replacement players to remain above the minimum of eight active players necessary to play an NBA game. Saturday night, the Nets and Magic played a game in which the two teams combined to have 24 players missing due to either injury or the health and safety protocols, and only 17 available players between them.

Several teams are hovering around the eight-player mark at the moment in addition to those that required postponements Sunday.