The 2pm kick-off was put back an hour as the club - who face Leeds Rhinos at Wembley on Saturday - awaited results.
However, with two players also having to stand down as a precaution, just five days before the club's first Challenge Cup final in 51 years, it is the news nobody wanted.
Today's Super League contest goes ahead at 3pm.
A statement read: "Salford Red Devils have had two rounds of routine Covid-19 testing since last Thursday’s Betfred Super League match against Huddersfield Giants.
"The results of the second round of testing were received this morning. Two players have tested positive, and have been required to self-isolate.
"The results of a further two players were inconclusive – they are also self-isolating as a precaution, ahead of further information being received.
"A further eight players have been ruled out of today's match through injury, but the decision has been taken to honour the fixture, in order to preserve the integrity of the competition.
"Training sessions were cancelled on both Sunday and Monday as a precautionary measure, meaning no additional players are impacted."