Salford lost 24-22 against Hull KR today in their final game before facing Leeds Rhinos in Saturday's Challenge Cup final.
But their plans were left in disarray after it emerged they suffered two positive tests and have another two players return inconclusive results meaning they must self-isolate.
Today's game had to be delayed by an hour and was almost called off as Salford - who had not suffered any positive tests previously - were hit badly ahead of their first Challenge Cup final in 51 years with two players even being injured this morning.
"There’s been a lot of disruption as we’ve basically not been able to train since the Huddersfield game (last Thursday)," explained Watson.
"It’s supposed to be one of the best weeks of your career going into a Challenge Cup final but this week’s been a massive frustration and disruption.
“We had one positive test on Friday. We had to then take the view of being over-cautious especially with Wembley coming up.
“It proved right as well as one more positive came back today and we think that’s from a family member who works at a school.
“On the whole, it’s just sod’s law it happens this week. On the whole we've done really well with it but it was going to happen at some point.
"But the boys showed their character. No one’s complained. We did a team over zoom last night, went in to do a session this morning and a couple of players got injured in that session even though it was a light run meant they couldn’t take part in this game as well.
"But they came out and played some old school rugby. Just tried to complete sets and defend well.
"For the whole game showed the character of what we’ve been about the last few years. They were great."
Salford only lost after Jamie Ellis' 80th minute penalty after Ed Chamberlain had scored an uncoverted try three minutes earlier.
Watson said; "We very nearly pinched a win at the end. If we’d been able to sub (Krisnan) Inu on to quickly take the kick we might have got the win there!
"Kris (Inu) was not even supposed to be on the bench and neither was Luke Yates. There was others who weren’t supposed to play either.
"I’m made up with Olly Roberts. He pulled up in the session today and we thought he’d get through five or ten minutes. Basically, the talk before the game was we’d kick off, he’d make one tackle and come off.
"The intention was probably not to use Inu or Yates and share the workload out.
"Inu put a hand up and sent a message saying he was prepared to play. I asked him to sit on the bench and he was getting itchy at the end
"No one’s complained about what’s happened. We had to have two days at home and thought the game might have to be cancelled with those injuries this morning.
"The payers knew we were talking to the RFL about maybe postponing the game but we didn’t want to do that and they showed great character going out there and playing like that."
He added: “We had to rejig this team. We didn’t want to compromise on this. We wanted to compete with them (Hull KR).
“But it may affect the Challenge Cup final team now.
“We’ll have to do a session tomorrow but it will be only light and we're probably not going to be contact for the rest of the week.
"Tyke (McCarthy) was a big one. It was important he got some minutes in before Wembley.