Dylan Napa, Brandon Wakeham, Corey Waddell, Sione Katoa and Aaron Schoupp are isolating after attending a COVID-19 exposure site in Sydney's east, seriously depleting the already injury-ravaged NRL side.

The five were given proposed fines by the NRL, while the Bulldogs intend to respond to a $50,000 breach notice for allegedly failing to properly communicate the imposed protocols to players.

In the meantime, Barrett has to field a team to face the Sea Eagles and says the players feel like they've let the team down.

"They are (disappointed), I've spoken to the five players and they're obviously disappointed, they feel as if they... it's put us in a bit of a position, put it that way," Barrett said.

"They are very disappointed with it but we'll wait and see what happens with the sanctions and the NRL and we're expecting the players to be back at training on Monday.

"They were very apologetic and they're proud of their club, no one likes to see that happen.

"We want this club to be held in a good light and it's something that we didn't really need at the time and they're fully aware of that.

"We'll have another chat when they get back in on Monday and see what sort of head space they're in."

Despite not having enough staff in the bubble to do 13 on 13 opposed sessions, Barrett said the team were able to have a full preparation ahead of the Sea Eagles game.

Falakiko Manu, Bailey Biondi-Odo and Chris Patol have been named to make their debut, while halfback Kyle Flanagan is set to return to first grade.

Meanwhile, the Bulldogs copped another blow on Thursday with representative winger Nick Cotric set to miss the rest of the year with a toe injury.

The 22-year-old suffered the injury at training this week in a freak accident.

Barrett said the specialist is not sure whether he will need to undergo surgery or not, but it looks as though his season is over.

"We were doing some ground work and he ruptured a ligament in his big toe out of nothing, just getting up off the ground," Barrett said.

"It was a really odd one, I'm shattered for Nick because he's an important part of our side and it looks like possibly being season ending."

It's the latest setback for the 15th-placed Bulldogs.

As well as the five players isolating, forward Adam Elliott is sidelined for six weeks with a fractured cheekbone, joining Ray Faitala-Mariner, Brad Deitz, Chris Smith, Jayden Okunbor and now Cotric in the casualty ward.

New Zealand test fullback Dallin Watene-Zelezniak was also released to the Warriors recently.

Australian Associated Press