Another three Barcelona players have tested positive for COVID-19, the club confirmed on Thursday.

It means Barca have seen as many as 10 players return positive results this week alone.

Sergino Dest, Philippe Coutinho and Ez Abde are the latest to go into quarantine, with Barca's numbers dwindling ahead of Sunday's trip to Real Mallorca.

Dani Alves and Clement Lenglet were the first two to test positive on Monday, followed by Jordi Alba and Alex Balde the following day.

Ousmane Dembele, Samuel Umtiti and Gavi were then added to that list on Wednesday when they also returned positive tests.

As such, Barca look set to be without at least 10 players for their first match of 2022, leading to suggestions it could be called off.

However, Spanish league regulations make postponements rare even amid the worst COVID-19 outbreaks.

Teams will still have to play so long as they have 13 available players from their first and second teams.

Clubs must continue to adhere to the rule that dictates a minimum of seven players registered to the senior team are on the pitch at the same time.

But that minimum can drop to five players if teams have fewer than seven professionals available for selection.

The Ashes series match referee David Boon has tested positive for COVID-19, Cricket Australia has confirmed.

Boon will now miss the fourth Test, starting on January 5, but is expected to return to take charge of the fifth Test nine days later.

The official is fully vaccinated – including a booster shot – and is asymptomatic. He will quarantine in Melbourne for 10 days before travelling to Hobart, where the final Test is set to be held.

Steve Bernard will serve as the referee in Boon's absence.

Boon is not the only person to miss out on the fourth Test, with England coach Chris Silverwood finding himself in the same position after a close contact contracted coronavirus.

There were four positive COVID-19 cases in the England camp on the second day of the third Test, but none of the players were affected.

Australia have already secured the Ashes, having won each of the first three Tests comfortably to move into an unassailable 3-0 series lead.

Kyrie Irving admitted it has been tough to watch the Brooklyn Nets from the sidelines as he marked his return to the practice court on Wednesday.

Irving returned to Nets' practice for the first time since preseason after the franchise decided in October to make him unavailable due to New York City's vaccine mandate and his unvaccinated status.

The Nets reversed that decision a fortnight ago when they announced the 29-year-old would return on a part-time basis for away games, despite remaining unvaccinated, with the side short on numbers following a surge of players in the NBA's health and safety protocols.

Irving's return to the practice court was delayed by him entering protocols a day after the Nets' announcement earlier this month, but he has now been cleared.

"I'm incredibly grateful just to be back in the building," Irving told reporters speaking for the first time publicly since mid-October. "Welcomed back with open arms [from] my teammates, the whole organisation.

"I'm not going to lie, it has been relatively tough to watch from the sidelines with everything going on in the world. I know everybody is feeling it. Just praying for everybody to be healthy during these times."

Irving will only be permitted to play away games and head coach Steve Nash said he would need a couple of weeks to get into NBA-ready condition.

"If I get the opportunity to get on the court and play with my teammates, even if it is just on the road for away games, I am grateful for the opportunity," Irving said.

"I've missed so much time. It's my first day back around the block with the guys and it felt like it's been a long time.

"It's only been, what, three months or so, but it has felt like the days have been slowly crossed off the calendar while I am sitting at home. When I thought about [returning to practice] last night, I could barely sleep.

"I understood their [the Nets'] decision and respected it. I really had to sit back and think and try not to become too emotionally attached to what they were deciding to do. I had to really evaluate things and see it from their perspective, meaning the organisation, my teammates.

"I really empathised, and I understood their choice to say if you are not going to be fully vaccinated, then you can't be a full [participant]."

The Nets are currently top of the Eastern Conference with a 23-9 record and play the Philadelphia 76ers at the Barclays Center on Thursday, which Irving will be unavailable for.

Five of the Nets' next six games are at home.

England coach Chris Silverwood will miss the fourth Ashes Test after a family member of the touring party tested positive for coronavirus.

Silverwood's position has come under question after England's dismal form in Australia, with the hosts having already retained the urn by racing into a 3-0 series lead.

Defeats in Brisbane and Adelaide were followed by a capitulation in Melbourne this week, with the third Test not even lasting three days.

Silverwood will be unable to be in attendance for the fourth match of the Tour in Sydney, as England desperately search for a result in order to avoid a whitewash.

A family member who travelled to Australia has tested positive for COVID-19 in the latest round of PCR tests administered to the touring party, the England and Wales Cricket Board (ECB) confirmed.

Silverwood will therefore have to isolate for 10 days, along with his family, in Melbourne. Another round of PCR tests will take place on Thursday.

The fourth Test is due to start at Sydney Cricket Ground on January 5, with the series finishing in Hobart after coronavirus regulations in Western Australia meant Perth was unable to host the final match.

NHL players who test positive for coronavirus and are fully vaccinated may only have to isolate for five days as part of changes to the league's health protocols.

Previously, any player or staff member to record a positive test would have to isolate for 10 days.

Outbreaks among teams this month caused the league to begin its Christmas break early and pause all games that involved cross-border travel between the United States and Canada.

However, following updated guidance from the USA's Centers for Disease Control and Prevention, the NHL and the National Hockey League Players' Association (NHLPA) agreed to modify regulations.

Players and team operations staff who test positive will now only have to isolate for five days, or, if they develop a fever, "until their fever resolves".

Asymptomatic individuals or those with improving symptoms will be cleared to return to practice and games if they provide a test that is either negative or falls within certain parameters.

They will also require medical clearance from team doctors and the permission of their local health authority. They must also wear a mask around others for another five days, except for during practice and games.

NHL medical experts will review the changes to the measures on or before January 12.

Thibaut Courtois has confirmed he is asymptomatic after returning a positive test result for COVID-19.

The Real Madrid goalkeeper, along with team-mates Eduardo Camavinga, Federico Valverde and Vinicius Junior, was confirmed by Los Blancos to have tested positive in the latest round of testing.

LaLiga leaders Madrid have had to deal with several positive cases within their squad over recent weeks, and are likely to be without the four players for at least their opening matches of 2022, against Getafe and Alcoyano respectively.

While Valverde and Camavinga have made 15 LaLiga starts between them this season, goalkeeper Courtois has started every top-flight match and winger Vinicius has played in all 19 league fixtures, scoring 10 goals and providing four assists.

His 14 goal contributions in LaLiga is topped only by Karim Benzema (22) in Madrid's squad, and the Brazil international could be a big miss for Carlo Ancelotti, while Courtois' steady presence will also be absent.

"Unfortunately, and despite complying with all the measures, I have tested positive for COVID," wrote the Belgium goalkeeper on Twitter.

"Although I do not have any symptoms, I am at home following the corresponding protocol and training to return as soon as possible. Thank you all!"

SAFE HANDS

Courtois has played every minute for Madrid in all competitions so far in 2021-22, with back-up Andriy Lunin yet to make a single LaLiga appearance for Los Blancos across the last two seasons.

The Ukrainian was one of six Madrid players to test positive for COVID-19 last week, though should be in line to return from isolation in time to face Getafe on January 2.

Only Leicester City's Kasper Schmeichel (26) has made more appearances of goalkeepers in Europe's top five leagues than Courtois (25) this campaign.

Of shot-stoppers to play at least 20 times, only Yassine Bounou (Sevilla) and Edouard Mendy (Chelsea) – both 15 – have conceded fewer goals than Courtois' tally of 19.

In LaLiga, Courtois concedes 0.84 goals per 90 minutes played, ranking him third out of goalkeepers to have featured at least 10 times in Spain's top flight this season.

Courtois' save percentage of 78.41, meanwhile, leads the way in Europe's top five leagues, out of goalkeepers to have played 20 games or more across all competitions, ahead of Mendy (77.61), and the former Chelsea man has made only one error leading to a shot, with that mistake not resulting in a goal.

Thibaut Courtois, Eduardo Camavinga, Federico Valverde and Vinicius Junior have all tested positive for COVID-19, Real Madrid have confirmed.

LaLiga leaders Madrid have had to deal with several positive cases within their squad over recent weeks, and are likely to be without another four players for at least their two opening matches of 2022.

Madrid issued a short statement on Wednesday confirming Courtois, Camavinga, Valverde and Vinicius were the latest players to test positive.

Los Blancos face Getafe in LaLiga on January 2, before travelling to Alcoyano in the Copa del Rey three days later.

David Alaba and Isco were confirmed to have tested positive for coronavirus on December 21, taking the total of Madrid players to have contracted the illness to eight in the space of a week.

Luka Modric and Marcelo had gone into quarantine after routine testing on December 15, and Gareth Bale, Marco Asensio, Rodrygo and Andriy Lunin then tested positive the following day, along with Carlo Ancelotti's son and technical assistant Davide.

While Valverde and Camavinga have made 15 LaLiga starts between them this season, goalkeeper Courtois has started every top-flight match and winger Vinicius has played in all 19 league fixtures, scoring 10 goals and providing four assists.

His 14 goal contributions in LaLiga is topped only by Karim Benzema (22) in Madrid's squad, and the Brazil international could be a big miss for Ancelotti.

Madrid will be hoping to welcome back the players in time for their home match against Valencia on January 8.

World number one Novak Djokovic has withdrawn from the ATP Cup in Sydney amid ongoing uncertainty over his title defence at next month's Australian Open.

Djokovic has not yet confirmed his place at January's Grand Slam due to the COVID-19 mandate in Victoria.

The 34-year-old's father, Srdjan, has previously said that the nine-time Australian Open champion is unlikely to feature in Melbourne unless vaccination rules are relaxed.

World number 33 Dusan Lajovic will now lead the Serbia team at the ATP Cup.

Meanwhile, Austria have been replaced by France at the event following the withdrawals of Dominic Thiem and Dennis Novak. The French will be led by world number 35 Ugo Humbert, alongside Arthur Rinderknech, Edouard Roger-Vasselin and Fabrice Martin.

Russia's Andrey Rublev, Aslan Karatsev and Evgeny Donskoy have withdrawn, with Evgeny Karlovskiy joining the team, while Team USA's Austin Krajicek has also pulled out.

The ATP Cup will begin on New Year's Day at both Ken Rosewall Arena and Qudos Bank Arena, Sydney Olympic Park.

Barcelona have confirmed Ousmane Dembele, Samuel Umtiti and Gavi have tested positive for COVID-19.

The Blaugrana were previously hit with positives for Clement Lenglet, Dani Alves, Jordi Alba and Alejandro Balde in the past week.

A statement on the club's website on Wednesday read: "The footballers Dembele, Umtiti and Gavi are positive for COVID-19 after PCR tests on the squad. 

"The players are in good health and self-isolating at home. The club has reported the cases to the relevant authorities."

Umtiti has largely been out of favour at Camp Nou this season, playing just once across all competitions, while Dembele has only managed eight appearances (four starts) having spent a significant period out through injury.

Gavi is the club's third-highest appearance maker in this campaign, though, with the 17-year-old midfielder playing 22 times, 17 of which have been starts. Only Sergio Busquets has featured more often.

The Blaugrana sit in seventh place in LaLiga, two points off fourth and 18 behind leaders Real Madrid, and travel to face Real Mallorca next on January 2.

The Brooklyn Nets can count on Kevin Durant and LaMarcus Aldridge again after they were cleared to return from NBA health and safety protocols.

Durant, who was in a rich vein of form, has sat out the Nets' previous three games, while Aldridge has not featured in the past five.

They could be back on court for Thursday's game against the Philadelphia 76ers at Barclays Center, the first of a run of three at home for the Nets.

Kyrie Irving has also been released from the shackles of the same COVID-19 protocols, the NBA said on its official website.

Because Irving is unvaccinated and cannot play home games due to local restrictions in New York City, his return to action must wait.

Irving has not played all season but could be in the frame to be involved in the trip to the Indiana Pacers on January 5 or at the Chicago Bulls a week later.

The Nets lead the way in the Eastern Conference with a 23-9 record, after following up a Christmas Day win over the Los Angeles Lakers by beating the Clippers on Monday.

James Harden, freshly out of protocols, played lead roles in both those wins with hauls of 36 and 39 points, and now he is set to have elite support.

Durant leads the Nets in scoring this season with an average of 29.7 points per game, alongside 7.9 rebounds and 5.9 assists. 

The Nets have had three recent games postponed due to their roster being hard hit by absentees.

Barcelona have announced that defender Jordi Alba has tested positive for COVID-19.

The left-back must now self-isolate, making him unlikely to be able to travel to face Mallorca on January 2 for Barca's next LaLiga game.

The 32-year-old becomes the third Barca defender to be sidelined with COVID-19, joining fellow full-back Dani Alves and centre-back Clement Lenglet.

Barca's official statement read: "First-team player Jordi Alba has tested positive for COVID-19, ruling him out of Tuesday afternoon's training session at Ciutat Esportiva Joan Gamper from 6pm CET.

"The player is in good health and self-isolating at home. The club has reported the case to the relevant authorities.

"He joins Clement Lenglet and Dani Alves on the sidelines, who also tested positive for COVID-19."

Xavi must now consider how to replace Alba in the side as he looks to steer Barca out of seventh place in the table and into the Champions League spots, with Rayo Vallecano two points ahead of them in fourth.

Only Sergio Busquets, Marc-Andre ter Stegen, Memphis Depay and Frenkie de Jong have played more minutes across all competitions than Alba's 1,526, highlighting his importance to the team.

The NBA has changed its health and safety protocols with players who test positive for COVID-19 now able to return to play in six days.

The change shifts the customary isolation period from 10 days to six, provided those players are asymptomatic and meet other testing standards.

Clubs were sent a memo by the league on Monday, coinciding with the Centers for Disease Control and Prevention cutting isolation restrictions for Americans who catch the coronavirus from 10 to five days.

Coronavirus numbers within the NBA has soared in recent weeks despite 97 percent of players being vaccinated.

Approximately 120 current NBA players were in protocols on Monday, with the likes of Giannis Antetokounmpo, James Harden, Kevin Durant and Jayson Tatum recently forced out.

The all-clear was given for day three of the Boxing Day Ashes Test to start on time after Australia and England players all tested negative for coronavirus.

There had been a scare ahead of the second day of the third Test in Melbourne when a member of the tourists' family group returned a positive COVID-19 result.

The England players and management were forced to remain at their hotel while they awaited their test results, before being given the green light to travel to the ground, with play starting half an hour later than scheduled.

Both sets of players took PCR tests after the second day of play and Cricket Australia on Tuesday confirmed all tested negative, meaning there were no delays for the third day.

The England team's support staff and the family members who tested positive on Monday – reportedly six people in total – are in isolation.

Australia were well on course to retain the urn after reducing Joe Root's side to 31-4 in their second innings after two days of play, with England trailing by 51 runs and 2-0 down in the series.

The NHL has postponed another three games this week as cases of COVID-19 continues to hit the league.

Games between the Chicago Blackhawks and Winnipeg Jets on Wednesday and a home-and-home set between the Dallas Stars and Colorado Avalanche on Wednesday and Friday will not be played.

That takes the number of games the NHL has now postponed up to 67 this season; a situation that led to the decision not to take part in the 2022 Beijing Olympics.

The league had planned to pause the season in February to allow players to take part in the Games, but that period will now be used to play some of the postponed games.

NHL Deputy Commissioner Bill Daly said last week: "We obviously will work very close with the (NHL) Players' Association. I do think we'll have to build in some off time during that three-week period for the players as they had anticipated previously.

"There are a lot of boxes to check there, but I expect that we'll be able to portion some portion of that break period to various clubs to get their players rested, and I hope to make full utilisation of the period so that we can make up the games that we've missed."

There is a "good chance" Brooklyn Nets star Kevin Durant will leave the NBA's coronavirus protocols this week, according to head coach Steve Nash.

The 11-time All-Star entered the health and safety protocols on December 18, but he could be out and ready to face the Philadelphia 76ers on Thursday.

Kyrie Irving, who went into protocols on the same day as Durant, is further away from a return to action.

"I think there's a good chance Kevin will be [fit for Thursday]," Nash told reporters.

"With Kyrie, I'm not so sure but it's coming. He's already been in protocols since December 18; he's got to be getting close."

Brooklyn earlier stated that Irving will re-join the NBA championship-chasing franchise for road games outside of New York and Toronto.

Irving is yet to play for the Eastern Conference-leading Nets this season due to his refusal to be vaccinated against coronavirus, which has prevented him from practising or playing with the team – New York has a mandate in place that states players must have had a COVID-19 jab.

At the start of the season, the Nets announced they would not accept Irving playing on a part-time basis and thus overlooked him for selection until he is vaccinated.

But due to injuries and a COVID-19 outbreak, Brooklyn have opted to bring Irving back.