Leicester Tigers have stopped training and closed their Oval Park training ground after several players and staff tested positive for Covid-19.
The Premiership club’s announcement comes 16 days before they are scheduled to start the new league season.
“As well as those who have returned positive tests, several [others] were also instructed to isolate, identified as close contacts,” the club said.
“Additional testing will take place on Friday [plus] Monday’s weekly testing.”
Tigers’ statement added: “All players will now continue their pre-season programme alone in their household bubbles while the Oval Park 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.”
On Wednesday, Premiership Rugby announced that 17 positive samples had come back from 718 tests carried out on players and staff in the latest round of pre-season testing.
Tigers finished 11th in the top flight last term and reached the European Challenge Cup semi-finals.