Cooper Cronk will have to train on Tuesday afternoon if he is to play for Queensland in Wednesday night's State of Origin series-opener against NSW.
But Queensland assistant coach Trevor Gillmeister is confident the star No.7 will overcome an ankle injury in time to take the field.
"I'm pretty confident he will play, but I'm no doctor," Gillmeister told Sky Sports Radio's Big Sports Breakfast.
"I think he's done everything possible to get himself on the field."
Cronk appeared unaffected when he arrived at Sydney Airport with the Queensland team late on Monday afternoon, and Gillmeister said Cronk had told him the ankle is now feeling "good".
But the Melbourne halfback is still yet to run on the troublesome right ankle since he rolled it at training on Friday and Gillmeister said head coach Kevin Walters had put a Tuesday afternoon deadline on the 32-year-old.
"I think Kevvie said he will have to train this afternoon," Gillmeister said.
"So that's the way it is and I suppose another 24 hours will make a fair difference but hopefully he's good to go this afternoon."
Queensland have lost their last two matches without Cronk in the past two years, while he also broke his arm early in the series-opener in 2014, which the Maroons went on to lose.
North Queensland playmaker Michael Morgan is expected to slot into the halves if Cronk is unavailable, with prop Jacob Lillyman slotting onto the bench, but NSW captain Paul Gallen doesn't believe it will come to that.
"We're preparing for him to play," Gallen said.
"I saw him walking around the airport yesterday pretty freely and I'm pretty confident he's playing to be honest."