CNN  — 

Covid-19 is causing headaches for professional leagues and university sports programs, who find themselves faced with having to reschedule games or find new opponents in the upcoming days.

The postponements and cancellations come as coronavirus cases rise throughout the country and an increasing number of players are asked to quarantine as part of Covid-19 protocols.

And it’s not just those who play under arena and stadium lights being affected. Those who perform under the stage lights of Broadway are also seeing an increase in canceled performances due to Covid-19.

Here’s a look at the changes to the sports schedule:

NFL postpones three games

The NFL postponed three Week 15 games due to Covid-19 issues, the league announced Friday.

Saturday’s scheduled game between the Cleveland Browns and the Las Vegas Raiders was rescheduled for Monday at 5 p.m. ET.

The decision came after 23 Cleveland Browns players landed on the NFL’s Covid-19/Reserve list in recent days, including the team’s starting quarterback Baker Mayfield. Browns coach Kevin Stefanski also tested positive for the coronavirus earlier this week.

“While our team and entire organization diligently prepared for tomorrow’s game as initially scheduled, both from an on-field and fan-experience standpoint, we respect the NFL’s decision to postpone our matchup against the Raiders,” the team said in a statement from chief spokesperson Peter John-Baptiste.

Sunday’s scheduled games between the Washington Football Team and the Philadelphia Eagles and between the Seattle Seahawks and Los Angeles Rams were also postponed until Tuesday. Both Tuesday games will kick off at 7 p.m. ET.

As of Friday, the Rams had placed 29 players on the Covid-19/Reserve list. The Washington Football team has 23 players on the Covid-19/Reserve list, including its first- and second-string quarterbacks.

“From the outset of the coronavirus pandemic, our focus has been to play our games in a safe and responsible way, consistent with the best available medical and public health advice, based on protocols jointly developed and implemented with the NFL Players Association,” Commissioner Roger Goodell wrote in a memo to each team.

The NFL describes the Covid-19/Reserve list as being for players who either test positive for Covid-19 or who have been quarantined after having been in close contact with an infected person or persons.

NFL teams not are permitted to comment on the medical status of players other than referring to roster status. Clubs may not disclose whether a player is in quarantine or is positive for the virus.

NBA postpones five games

The NBA announced the postponement of five games due to Covid-19 issues within several teams in the league.

The Brooklyn Nets, Cleveland Cavaliers, Orlando Magic, and Philadelphia 76ers each have large portions of their rosters and other team staff in the league’s Health and Safety protocol.

Sunday’s scheduled games between the Nets the and the Denver Nuggets as well the Cavaliers game against the Atlanta Hawks and the 76ers versus the New Orleans Pelicans were postponed.

Monday’s game between the Magic and the Toronto Raptors was also postponed, as well as Tuesday’s game between the Nets and the Washington Wizards.

No details were provided about rescheduling of the affected games.

NCAA teams postpone games or find new opponents

The NCAA men’s basketball calendar has been turned upside down with more than a dozen games canceled or postponed in recent days.

Most notably, games between No. 2 Duke and Loyola and between No. 4 UCLA and North Carolina scheduled for Saturday were canceled due to Covid-19 issues within the UCLA and Loyola programs, the schools announced Friday.

The Tar Heels ended up playing the Kentucky Wildcats in Las Vegas, who had been scheduled to play Ohio State in the same arena at the CBS Sports Classic. The Wildcats dominated the game, winning 98-69.

Two other men’s top 25 games were canceled. No. 16 Seton Hall was to play Iona, but officials said the game cannot be played because of Covid-19 protocols at Seton Hall.

Seton Hall also will forfeit Monday’s Big East Conference game against St. John’s, the league announced. While the forfeit counts as a conference loss, it does not affect the Pirates (9-1) overall total number of losses.

No. 23 Colorado State canceled its games against Tulsa Saturday and against No. 6 Alabama on Tuesday because the 10-0 Rams have “Covid-related concerns.” The games will not be made up.

In women’s basketball, No. 19 Kentucky’s game against Morgan State, which has Covid-19 issues, was postponed.

The University of Miami forfeited Sunday’s Atlantic Coast Conference game to No. 15 Duke.

More NHL postponements

The NHL announced 27 games had already been postponed as of Saturday. On Sunday, the league and NHL Players Association jointly announced at least 12 more games that were postponed through December 23 because they involved travel between the US and Canada.

“With the number one priority of maintaining the health and safety of our NHL community, and amid changing and unpredictable conditions, we are determined to remain flexible and adaptable both in terms of scheduling and in adjusting Protocols as necessary,” the joint statement read.

The NHL and NHLPA are also “actively discussing the matter of NHL Player participation in the 2022 Winter Olympics in Beijing, China, and expect to be in a position to announce a final determination in the coming days,” the statement read.

The league announced Sunday that all games involving the Detroit Red Wings will be postponed through December 26 due to an uptick in Covid cases. It’s yet to be determined when the team’s practice facility will re-open. That decision will be made jointly between the NHL and Players’ Association.

Six NHL teams have now been forced to shut down in the past week as the Red Wings join the Boston Bruins, Nashville Predators, Calgary Flames, Colorado Avalanche and Florida Panthers.

The NHL’s Colorado Avalanche and Florida Panthers will shut down through December 26 due to “concern with the number of positive cases within the last two days as well concern for continued Covid spread in the coming days,” the league announced.

The Avalanche will see four games postponed, while the Panthers will push back three games.

The NHL also extended the Calgary Flames’ shutdown through December 26. The Flames will have missed six games since its shutdown began Monday. As of Wednesday, the Flames had 16 players in the NHL’s Covid-19 protocols.

In addition, Saturday’s game between the Montreal Canadiens and Boston Bruins has been postponed. As of now, the Canadiens will play the New York Islanders Monday.

CNN’s Kevin Dotson and Alaa Elassar contributed to this report.