Kolodjashnij was subbed out of Saturday's thrilling win over the Magpies with the issue, being replaced by utility Mark O'Connor.
The club confirmed on Monday evening that scans on Kolodjashnij's injured leg have come back showing a "tibiofibular joint injury", with Geelong yet to determine the 27-year-old's likely return timeframe.
The Cats have been awarded the week off thanks to their qualifying final win over Collingwood, giving Kolodjashnij and the club time to prepare for their preliminary final in two weeks' time.
Geelong's head of medical Harry Taylor revealed that the club have some way to go before confirming Kolodjashnij's likely playing status.
"We have had positive news, with subsequent scans showing a tibiofibular joint injury that the Medical & Conditioning team will treat and manage accordingly," Taylor told Cats Media.
"Jake’s availability for the Preliminary Final will be determined closer to the game."