NSW captain Andrew Johns is in serious doubt for Wednesday night's third State of Origin rugby league match after a dose of flu worsened on Saturday night.
Coach Phil Gould said on Sunday that Johns' illness had spread to his chest and Bulldogs halfback Brent Sherwin had been put on standby to replace the Blues' matchwinner.
Johns was not travelling to Brisbane with the team on Sunday, staying behind with team doctor John Orchard to monitor his condition.
"Joey woke up very sick yesterday morning and it got worse as the night went on," Gould said on Channel Nine.
"He's got a bit of flu and it's down in his chest.
Gould said Johns would be given until the last moment to be passed fit to play in the match, where the Blues will chase a series clean sweep, but the outlook was not good.
"The doctor rates it a lot worse than Shaun Timmins' (bout of flu) last year and he pulled out on game day," Gould said.
The Blues also have concerns about second rower Luke Ricketson and centre Matt Gidley who also have flu symptoms and were expected to be isolated from their teammates.