The 31-year-old was sighted on crutches at Simonds Stadium on Tuesday morning.
He headed off to have scans on his foot a short time later.
"Stevie came off the track today with a bit of foot soreness from the game (against Fremantle)," club physio Mark Young told CatsTV.
"We're going to send him for some scans and then pending those results we’ll make a scan later in the week."
Johnson, who battled a back problem during the middle part of this season, has had a rollercoaster couple of weeks.
He was cited by the Match Review Panel for kneeing North Melbourne's Scott Thompson after Geelong's win over the Kangaroos in round 19, and initially offered a one-match suspension, but was cleared after contesting the charge at the Tribunal.
The let-off enabled Johnson to resume his rivalry with Fremantle tagger Ryan Crowley on Saturday night.
The pair was involved in repeated scuffles throughout the game, which the Cats won by two points.
Johnson largely held his nerve during the battle with Crowley, although he was restricted to just 15 disposals.
But he drew attention to himself by nudging Fremantle's Lachie Neale in the head with his boot during the first quarter.
The MRP scrutinised the incident before electing to clear Johnson of any wrongdoing.
