The Scottish Government will decide if Celtic players must self-isolate from Monday after the club's winter training camp in Dubai.
Sam Querrey, who was sanctioned by the ATP for breaching COVID-19 protocols at the St Petersburg Open in October, has defended his actions.
The schedule for Australia's Test series with India is under threat, with the tourists reportedly unhappy with Covid rules.
The FA have told clubs taking part in the FA Cup third round that they should field a team if they have at least 14 fit players, as they seek to avoid a fixture pile-up.
West Ham manager David Moyes wonders if Premier League rules have changed since he tested positive for coronavirus earlier this season.
The BNP Paribas Open, due to take place at Indian Wells in March 2021, has been postponed due to coronavirus concerns.
Rochdale's club doctor Wes Tensel has called for the EFL to see the "bigger picture" and halt the current campaign due to rising cases of coronavirus.
England are looking to appoint a permanent member of staff to supervise mental health as players spend time in bio-secure bubbles.