Scarlets’ Heineken Champions Cup match at home to Toulon on Friday has been called off.
Toulon pulled out because of concerns about a Scarlets player testing positive for Covid-19 after playing against Bath last weekend.
The Welsh side withdrew the player and his close contacts from training before naming their side to meet Toulon.
The action satisfied European rugby organisers but not the Toulon management.
The French club’s decision to pull out came as a shock to the home side, who arrived at their Parc y Scarlets home as normal around two hours before the scheduled 17:30 GMT kick-off on Friday.
Bath’s match with La Rochelle was called off because the English club said they had 12 players self-isolating after being in close contact with the Scarlets player last weekend.
A Toulon statement read: “Rugby Club Toulonnais learned this Thursday, 17 December that at least one player from the Scarlets team had tested positive, earlier this week, for Covid-19.
“Following this, the Bath Rugby club, which had faced the Scarlets last weekend, were forced to forfeit the second day of the Champions Cup because 12 players in their squad had been in ‘close contact’ with this Welsh player.
“Despite this eminently delicate context, the EPCR, with the approval of the Welsh Rugby Federation, wished to maintain the Scarlets / Toulon match.
“President Bernard Lemaitre spoke extensively with EPCR Director General Vincent Gaillard.
“He specified that the sanitary conditions were not met to maintain the organization of this meeting the health of the players of the staff and their families being paramount.
“The EPCR nevertheless upheld its decision.
“Faced with this state of affairs, the Rugby Club Toulonnais, although aware of the serious consequences, decided not to play this meeting as planned this evening.”