GEELONG coach Chris Scott says the club will wait until Friday to fully test Steve Johnson's knee, which means he will be selected in the Cats' Grand Final team on Thursday night.

Johnson missed Geelong's open training session that drew about 6,000 fans to Skilled Stadium on Tuesday.

He and the club's medical staff are trying everything they can to help him recover from the wrenched knee he suffered in the preliminary final win over West Coast.

This includes regular trips to Melbourne to use a hyperbaric chamber, which can aid recovery by increasing the amount of oxygen in a person's blood.

"He's coming along pretty well, but we're really not going to have anything definitive until Friday," Scott said.

"At the moment, we think he's a chance. He certainly hasn't been ruled out, but he's certainly not a definite starter.

"You're never going to get significant enough improvement in the first three or four days [to make a concrete decision].

"And we haven’t tested it, and we won't do so until Friday.

"We've taken that approach all year with our players, and even though this is a little bit different in that there's no next week, we need to be [consistent]."

Scott says a decision on Johnson's fitness could be left as late as Saturday morning.

The coach says that to be declared right to play Johnson will need to prove that he "can perform somewhere close to his top level".

As for how close to 100 per cent that must be, Scott stated: "99."

He continued: "We've got a big group of players that can all contribute. We'd love to have Stevie somewhere near 100 per cent, but if he's not, we'll bring in guys that are 100 per cent.

"[The decision] will be extremely difficult in a sense, but in another sense, he's either right or he's not.

"Our medical staff will make that decision, and we'll back them in as we have all year."

Veterans Cameron Mooney, Darren Milburn and Shannon Byrnes, who were the three emergencies for last weekend's game against the Eagles, all trained strongly on Tuesday.

It is likely that one member of the trio will take Johnson's place if he is unable to prove his fitness.