Ospreys' Pro14 game with Connacht on Saturday has been postponed after a player in the Welsh region's squad returned a positive coronavirus test.
Other players have been identified as close contacts and the Pro14 medical advisory group deemed the fixture could not go ahead.
It will now be rearranged to take place in early 2021.
The postponement comes a day after Scarlets' match with Leinster was called off over a Covid-19 outbreak.
Benetton, who lost 24-22 to Ospreys on Sunday, carried out routine squad testing this week and returned negative results all round.
It is the third game to be called off for Connacht this season after previous postponements against Benetton and Dragons, who themselves have had to rearrange a trio of matches.