(CNN) Some big names joined the Covid-19 protocol lists in the NBA, NFL and NHL on Tuesday and Wednesday.
Two of the leagues have been forced to postpone games due to outbreaks and all three are losing key players due to the Covid-19 protocols. They include the man who dropped 50 points in Game 6 of the NBA Finals, a former NBA MVP and a three-time NFL Pro Bowler.
But they weren't the only players sent to the sidelines as the number of players testing positive -- like Covid-19 case numbers in the US -- is on the rise.
Here's a look at recent Covid news from the three big professional sports leagues:
Milwaukee Bucks star Giannis Antetokounmpo -- the reigning NBA Finals MVP -- became the latest prominent player to enter the league's health and safety protocols. He will miss Wednesday's game against the Indiana Pacers, according to the Bucks' injury report.
Meanwhile, the Brooklyn Nets announced ahead of their game Tuesday against the Toronto Raptors that their list of players in the protocols has grown to seven with the addition of star James Harden.
The team is already missing All-Star guard Kyrie Irving, who has yet to play this season because he is not adhering to a vaccine mandate in New York City.
On Monday, the NBA postponed games for the first time this season because of Covid-19.
With 10 players and additional staff members in the health and safety protocols, the Chicago Bulls' scheduled games for Tuesday and Thursday were postponed. And the team's game against the Los Angeles Lakers on Sunday was moved from 2:30 p.m. CT to 7 p.m.
The Lakers canceled practice in Los Angeles on Tuesday. No reason was given but according to ESPN, the decision was due to Covid-19 concerns.
ESPN reported the practice was canceled after guard Talen Horton-Tucker returned a positive coronavirus test, citing a team announcement.
Horton-Tucker is now on the Lakers' health and safety protocols list.
Players on the protocols list must quarantine for 10 days or have two negative tests in a 24-hour period. Bulls players have entered the protocols on different days over the past weeks.
A league source told CNN last week that 97% of NBA players are vaccinated, with 60% of eligible players having received a booster shot. There are about 500 players across 30 rosters.
No major professional sports league in the United States has required its players to be vaccinated.
Dozens of NFL players have been added to the league's Covid-19/Reserve list in the past few days, including 14 from the Cleveland Browns since Tuesday alone.
The Browns placed six players on the list Wednesday, including starting quarterback Baker Mayfield. That's in addition to eight players -- including five-time Pro Bowl wide receiver Jarvis Landry and two-time Pro Bowl tight end Austin Hooper -- that the team added Tuesday.
Also, Browns head coach Kevin Stefanski tested positive for Covid-19 -- and could miss Saturday's home game against the Las Vegas Raiders, the Browns said Wednesday.
"Should Coach Stefanski not produce two negative tests by Saturday, special teams coordinator Mike Priefer will serve as acting coach and offensive coordinator Alex Van Pelt will serve as the play caller in Saturday's game," The Browns said in a news release.
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. Per NFL-NFL Players Association policy, clubs are not permitted to comment on a player's medical status other than referring to roster status. Clubs may not disclose whether a player is in quarantine or has tested positive for Covid-19.
A National Football League source told CNN that 28 players tested positive for the novel coronavirus on Tuesday. The league saw 37 positive tests among players Monday, a league source said.
The total from Monday and Tuesday alone more than doubled the 29 positive tests from players from November 14 to 27, the last public release of testing data from the NFL.
Among dozens of additions to the league's Covid-19/Reserve list, the Browns and Los Angeles Rams were most heavily impacted. The Rams had 13 players on the list as of Tuesday, including nine added that day.
The Rams' Tuesday additions were headlined by three-time Pro Bowl wide receiver Odell Beckham Jr., who scored a touchdown in the team's Monday night win over the Arizona Cardinals.
"We had to close our building down. This Covid thing has taken over kind of all the things that we're dealing with right now," Rams head coach Sean McVay said Tuesday. "We're in intensive protocols. We're remote today. We will be remote tomorrow."
Before Stefanski's positive test was announced, the Browns coach described the protocols his team was observing Tuesday.
"We are in the intensive protocols, which means you are wearing masks in the building, virtual meetings, cafeteria is just grab and go and those type of things, but we will get our work in," Stefanski told reporters Tuesday. "That is what we do. We have done it before. We will have our virtual meetings, and then when we are on the practice field, we will make sure that we are locked in and ready to go."
The NHL postponed Tuesday night's game between Carolina and the Minnesota Wild due to multiple Hurricanes' players testing positive for the novel coronavirus.
The Hurricanes have six players in the league's Covid protocol. The NHL announced Tuesday that Ian Cole, Steven Lorentz, Jordan Staal and Andrei Svechnikov tested positive for the virus.
On Monday, the team revealed Sebastian Aho, Seth Jarvis and a member of the training staff entered protocol while the team was in Vancouver, Canada. The Hurricanes lost to the Canucks 2-1 on Sunday.
Tuesday's postponed game was slated to be played at the Xcel Energy Center in St. Paul, Minnesota.
The NHL has postponed nine games this season due to Covid-19 protocols.
The Calgary Flames, who on Monday postponed their next three games, now have 16 players in the league's Covid protocol with the addition of seven players -- Rasmus Andersson, Byron Froese, Johnny Gaudreau, Erik Gudbranson, Trevor Lewis, Jacob Markstrom, Tyler Pitlick -- on Wednesday.
The other nine players placed in the protocol since Monday are Noah Hanifin, Milan Lucic, Sean Monahan, Elias Lindholm, Andrew Mangiapane, Brad Richardson, Adam Ruzicka, Chris Tanev and Nikita Zadorov.
Head Coach Darryl Sutter, two assistant coaches and seven support staff members are also in the protocol, the team said Wednesday.
The impacted games for the Flames, second in the Pacific Division, have yet to be rescheduled.
The Boston Bruins played a home game Tuesday night against the Las Vegas Knights but they were without two of their top wingers, Brad Marchand and Craig Smith, who were put into the NHL Covid protocol.
According to media reports, the Colorado Avalanche, Edmonton Oilers, Florida Panthers, New York Islanders, Philadelphia Flyers each had a player enter the protocol on Tuesday.
In addition, the Vancouver Canucks said three players were put on the list before Tuesday's game against the San Jose Sharks and one was pulled from the game and placed in the protocol.