Leicester have stopped all training and closed the club's training ground just under two weeks before the start of the new Gallagher Premiership season following an outbreak of Covid-19.
The club returned several positive coronavirus tests earlier this week, including players and members of support staff.
Tigers' first game of the 2020-21 Premiership campaign is scheduled to be at home to Gloucester on November 21.
In addition to the players and staff who have returned positive tests, several other members of the squad and support team have been instructed to self-isolate after being identified as close contacts.
"Tigers have made the decision to pause all training commitments and close the training ground in a bid to maintain the integrity of the 2020-21 Gallagher Premiership season, as well as honouring our responsibilities to the Leicestershire community," read a club statement.
"Leicester Tigers takes its responsibility to maintain high standards extremely seriously at this time and is confident in the measures in place.
"All players will now continue their pre-season programme alone in their household bubbles while the Oval Park (training) facility remains closed.
"Health, wellbeing and safety are paramount and all players and staff are being monitored by Tigers medical staff, in addition to their families being offered support where necessary."
Leicester, who finished second bottom last season, intend to carry out additional testing of all players and staff on Friday ahead of Monday's weekly testing in line with Premiership Rugby guidelines.