GEELONG does not know the full extent of superstar midfielder Patrick Dangerfield's hamstring injury, with the Cats to determine over the coming days his chances of playing against Melbourne in round one.

Dangerfield left the field of play in the opening quarter after pulling up short as he went to kick the ball inside 50 during Sunday's JLT Community Series clash against Essendon at Central Reserve in Colac.

Cats assistant coach Corey Enright said the club would have to get Dangerfield's hamstring scanned before knowing the severity of the injury.

"We know there's tightness in his hamstring and he got pulled from the game," Enright said.

"Over the next couple of days are the most important days that we'll get some more information around that and we'll see how he is.

"It's obviously really early to tell how significant it is but there's something there so we need to get the scans and talk to the medicos and see where it lands in the next couple of days."

The Cats are still unsure if returning star midfielder Gary Ablett (hamstring) will be fit for the opening round against the Demons as he continues to recover from a hamstring strain.

Enright said Ablett would give himself every chance to prove his fitness for the game against the Demons.

"He trained today with the guys that are not playing at all today," Enright said.

"He's done a few running sessions now and his preparation is going really well."

Athletic ruckman Rhys Stanley is another Cat in significant doubt for round one after straining his calf against the Bombers on Sunday.

"It was significant enough to pull him from the game and we'll just have to get the scans and see how many weeks it'll be from there," Enright said.

Nakia Cockatoo (calf), Stewart Crameri (knee) and Sam Menegola, who was a late withdrawal with calf soreness, will also have to prove their fitness ahead of round one.

The Cats' VFL team has a practice match against Werribee at GMHBA Stadium next week and Enright said all three were chances to play in that game to build up their match fitness.

"They're all on their specific plans and they're all at different stages as to where they're at," he said.

"All three of those guys have had footy training and running training underneath their belts, so it's just fine-tuning for the next couple of weeks."

Lachie Henderson (knee) and Scott Selwood (ankle) have all but been ruled out of round one after restricted preparations leading into the season.