NSW captain Boyd Cordner is expected to join teammates for the first time this week when the Blues continue preparations with a field session on Saturday.
Cordner's status for the State of Origin decider has been under a cloud since picking up a calf injury in game two that has so far prevented him from running.
"He'll try and do a bit of running today maybe, we'll see when we get out there," teammate Wade Graham said before training on Saturday.
"He's in good spirits, so we've all got our fingers crossed for him and obviously we'll know more over the weekend when he really starts testing it out."
Graham admits Cordner's possible withdrawal would be a huge loss five days out from the game.
"He's our captain. We've been fortunate enough to be able to keep the same side throughout the series, it wouldn't feel quite the same if Boydy's not there," he said.
"But we're all pretty positive and he's in a good frame of mind which is important. Time will tell."
Should Cordner fail to recover in time, Graham is expected to fill the left-edge role, with 18th man Jack de Belin promoted to the bench for what would be his Origin debut.
Graham said the St George Illawarra backrower would be ready to produce if called upon.
"Even when you come to these camps as 18th man with no injuries, that you prepare as if you're going to play anyway. That's your job," he said.
"You do that in NRL. These days they have 18-19 players you carry each week because the game's pretty fickle - one little thing and there can be injury."