The Roosters hooker met with the independent neurologist on Thursday morning and had another appointment scheduled for Thursday afternoon.
It would be Watson's final game as a Rooster after signing deals to join St George Illawarra in 2027 and the Papua New Guinea expansion side from 2028.
He was all smiles at the grand final fan day event in the Sydney CBD on Thursday as the club continued to have faith in his fitness.
"He had an appointment this morning that went well and he's got another one this afternoon," coach Trent Robinson told the sea of fans.
"It's out of our hands so we'll get a ruling on that either tonight or tomorrow and he'll either be in or out."
The NRL's protocol requires any player diagnosed with a category-one concussion, like Watson was in the preliminary final win against the Dolphins, to be automatically sidelined for 11 days.
The initial ruling by the independent doctor was revised to a category one after it was originally treated as a less severe category two, which does not require the mandatory stand down period.
The Roosters are appealing that change, desperate to get the former Newcastle player into the decider against his former side.
"Connor has played his key role in the balance of our team in the middle of the game. He has really done that well, he is fit, he plays multiple positions, and he is in our 17 every week for a reason," Robinson said.
"We want him to play, deserves to play, whether he is fit to play will get decided by somebody else, and then we will adapt."
Even the opposition is hoping that Watson will be available to play in his first grand final.
Newcastle captain Kalyn Ponga will relish the chance to line up against his former flatmate in the biggest match of their careers.
"The injuries that he's had to overcome throughout the years, the adversity, he's one of the most deserving blokes to be in a grand final,
"If he gets cleared, yeah, I'll be stoked for him, but obviously if he doesn't, then he's gotta take care of his health first," the Knights fullback said.
The Roosters' three time premiership-winning coach dropped hints about who could replace Watson if he is deemed unfit to take the field.
"I don't think it takes too much to work out what plan B is, but we have got some really good hookers," he said.
"Benaiah Ioelu played some great footy for us this year. He brings a lot of energy to us as well so he will come into consideration then."
