Billy Slater is set to make a remarkable return from injury and play in next week's Origin decider after being named in Queensland's 20-man squad.
The influential full-back has started running less than two weeks after tearing the posterior cruciate ligament in his left knee.
North Queensland's Matt Bowen has been named in the squad as potential cover for Slater, but Queensland coach Mal Meninga is growing in confidence the Storm superstar will be right for the July 4 showdown with New South Wales.
"Billy ran yesterday morning and he was very upbeat about that session so we're going to give him another five days until the end of the week to make that final decision," Meninga said.
"At this stage we're very hopeful but uncertain (whether he'll play). We can't make any judgements on that, only Billy and the medical staff (can make that decision).
"Billy certainly wants to play, he's desperate to play so that's why we're going to give him the extra time, I think he deserves that respect."
Slater is currently in Melbourne receiving treatment under the supervision of the Storm's medical staff.
Pressed on when he'll make a final decision on Slater's availability, Meninga revealed: "We'll make a decision going into the weekend, obviously we want to prepare really well for game three and the weekend is really critical to us.
"Saturday would be the latest (and he'll need to be running near full pace)."
If Slater does not make it, the Maroons have the option of using Bowen or switching Greg Inglis to number one and bringing Dane Nielsen into the centres.
While Meninga is sweating on Slater's availability, he also has concerns over Sam Thaiday (shoulder) and Justin Hodges (ribs) ahead of the Suncorp Stadium clash.
Lock Ashley Harrison (toe) was ruled out on Monday, with Brisbane's Corey Parker likely to start in his place.
Ben Te'o looms as Parker's replacement on the bench.
Prop Matt Scott is expected in camp later in the week following his mother's funeral on Wednesday.
Meanwhile, Meninga praised Canterbury-Bankstown full-back Ben Barba's recent form but the coach concedes he wasn't prepared to gamble on a rookie in the series decider.
"Benny was part of our squad in Game Two, he's had a fantastic year so far and was exceptional on the weekend," he said.
"We felt experience was probably the key here, being a decider at Suncorp Stadium, State of Origin's a huge event so we decided to go with experience."
Full Queensland squad: Billy Slater; Darius Boyd, Greg Inglis, Justin Hodges, Brent Tate; Johnathan Thurston, Cooper Cronk; Matt Scott, Cameron Smith (c), Petero Civoniceva, Nate Myles, Sam Thaiday, Corey Parker; Matt Gillett, Dave Taylor, Ben Hannant, David Shillington, Dane Nielsen, Ben Te'o, Matt Bowen.