Wigan's Betfred Super League fixture against Catalans Dragons on Thursday has been postponed after three members of the Warriors' backroom staff tested positive for Covid-19.
The club say a member of the first-team coaching staff and two from the support team returned positives from the latest round of testing and all three are self-isolating in line with Government guidelines.
Wigan had three positive tests among their players a week ago but say one of them has since returned two negative tests and is waiting to get the go-ahead to return to training. The other two are continuing to self-isolate.
The club cancelled Wednesday's scheduled training session and will have a further round of testing on Thursday. Their next scheduled fixture is against Salford next Friday.
It is the second time the Catalans fixture has fallen victim to the coronavirus and plans to rearrange the game for Sunday fell through when the French club said they were unable to rebook their charter flight.
With few gaps in the five weeks left of the regular season, it looks increasingly unlikely that all the remaining fixtures will be fulfilled.
A Super League spokesman said: "As yet, there is no new date available in the calendar but the situation will be kept under review."
The Rugby Football League has already announced that league positions will be determined by win percentages in such an event.
The first major final of the season will go ahead at Wembley on Saturday and Salford received some good news when co-captains Lee Mossop and Mark Flanagan were cleared to face Leeds in the Coral Challenge Cup.
The Red Devils announced on Tuesday that two unnamed players were self-isolating after contracting the virus and that two others were stood down from the Super League game against Hull KR after their Covid-19 results proved inconclusive.
Salford on Wednesday received negative retest results and that will be a massive relief to the club as they prepare for their first Challenge Cup final appearance for 51 years.
A statement from the club said: "After receiving inconclusive Covid-19 test results earlier this week, Salford Red Devils are pleased to confirm that both players' retests have returned negative.
"This means that both players will now be able to return to training."
Salford will still be without the two players who have tested positive and their identity is likely to be revealed when head coach Ian Watson names his 21-man squad on Thursday.
But having prop forward Mossop and back rower Flanagan available is good news for Watson.
Both players were guaranteed to be in his plans and for Flanagan it will be an opportunity to end his career on a high as he prepares to hang up his boots at the end of the season.
In total, from 591 tests taken across the 11 Super League clubs and other support staff this week, there have been seven positives spread across four clubs.