Geelong may be forced to change its ruck combination for the big clash against Fremantle on Sunday, with Dawson Simpson facing a fitness test after he suffered a shoulder injury against Hawthorn.

The Cats' big man suffered a minor AC joint sprain early in the game leaving him in doubt to take on star Freo Docker Aaron Sandilands.

Simpson was eventually subbed off during the third term as he struggled to have an impact on the game and would have been in a battle to retain his spot anyway with both Rhys Stanley and Hamish McIntosh pressing their claims.

Stanley played in a VFL practice match on Saturday and came through the game with no issues after a hot spot in his tibia caused him to have a delayed start to the season.

McIntosh has been in good form in the VFL and has the experience to take on Sandilands.

Premiership-winning duo Andrew Mackie, a late withdrawal on Monday due to quad tightness, and Jimmy Bartel, who was concussed in the final minute against Hawks, both will need to pass tests to play against Fremantle. 

"[Mackie's] feeling much better now. He'll have some boxes to tick this week, so he will be a test," Geelong physiotherapist Mark Young told the club's website.

Bartel will be monitored throughout the week and will have to pass concussion tests to be declared available.

"The good news is Jimmy is feeling better. The doctor and Jim will have a conversation each day through the week. His wellbeing has obviously been our main concern," Young said.

The Cats are also pleased running defender Jackson Thurlow got through the VFL unscathed in his first match since suffering a lacerated kidney.

But youngster Jarrad Jansen will be out for three weeks after he strained a hamstring at training.