Vaughan found himself at the centre of a storm on Thursday after going out for breakfast in contravention of the NRL's strict biosecurity protocols amid the COVID-19 pandemic.

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It saw him immediately ordered into a 14-day quarantine period, forcing him out of the 24-16 loss to the Roosters and also ruling him out of next Friday's clash with Parramatta.

It was a disruption the Dragons could ill-afford with their finals hopes hanging by a thread, and McGregor didn't mince words in the aftermath to Thursday's defeat.

"We're well aware of what our responsibilities are, we talk about it consistently, so there's no reason for it other than it was selfish behaviour really," McGregor said.

"I haven't spoken to him. We've got a WhatsApp group and I explained the punishment that's been handed to him by the NRL, then concentrated on what we needed to do today.

"It's not what you need from one of your senior players, someone that's important to your footy team. It's disappointing if it was anyone. It's just a behaviour that you shouldn't do.

"We spoke about (doing) whatever it takes and doing the right thing by one another, making sacrifices and that's just one of them. The game's done a lot to get back going so we've got to be respectful of that."

Vaughan's presence was sorely missed in the middle of the park, with Siosiua Taukeiaho producing a dominant 80-minute effort in the absence of a number of other stars.

The Dragons forwards depth will be tested further in the coming weeks, with Tariq Sims leaving the field midway through the second half with a shoulder injury.

Young-gun Jackson Ford could also be looking at enforced stint on the sideline after being placed on report for an ugly looking trip on Roosters star Luke Keary,

"I did see it, the leg went out, no one was hurt, he didn't hit him so I'm not sure what will happen there," McGregor said.