After a cluster of postponements this week, the NHL has mandated additional in-arena protocols to help reduce the spread of COVID-19, sources confirmed to ESPN.

Beginning with Thursday's games, the glass will be removed behind the teams' benches, sources said. The belief is this measure will help increase airflow in arenas.

Sources also said that players and coaches are no longer allowed to arrive to arenas until one hour, 45 minutes before puck drop -- with an exception for players receiving medical treatment. Teams also are being asked to use additional locker room space for themselves and opponents to help enforce better social distancing. The league also is considering asking teams to use portable air cleaners behind the benches "to improve indoor air quality and mitigate airborne viral transmission."

Sportsnet first reported on these changes.

There had been some concern raised by teams about the lag time between daily PCR testing and puck drop. The NBA also began its season with daily PCR testing but switched to rapid tests to get results before tipoff.

In an email, deputy commissioner Bill Daly said the NHL already uses rapid testing "where deemed helpful or necessary."

"I would say we are committed to layering in more rapid testing as we go forward," Daly said.

Three teams -- the New Jersey Devils, Buffalo Sabres and Minnesota Wild -- had to temporarily shut down their season and postpone multiple games due to the NHL's COVID protocols.

Since the season began Jan. 13, 22 games have been postponed and around 90 players have appeared on the league's COVID protocol related absence list. A player's status on the list doesn't necessarily mean he tested positive for the coronavirus; often, a player can end up on the list if he is deemed a close contact or because of travel and quarantine restrictions.