GEELONG defender Tom Stewart will undergo surgery on Tuesday to repair the fractured eye socket he suffered in Sunday's dramatic win over Fremantle.

The Cats remain uncertain as to how many weeks the 24-year-old will be forced to miss and expect to have a clearer indication after his operation.

Stewart was one of Geelong's best players in the first half before he clashed heads with Fremantle's Hayden Crozier when attempting to spoil just before half-time.

He went to hospital after the game but was home on Monday and will be operated on in Geelong on Tuesday.

Stewart has made an outstanding start to his AFL career, playing 12 games after being drafted with pick No.40 in the 2016 NAB AFL Draft.

Meanwhile, skipper Joel Selwood was in at Simonds Stadium on Monday after being concussed in the first 45 seconds of Sunday's game.

No decision has been made on whether he will be available for Saturday's clash against Greater Western Sydney.

He is expected to undergo concussion tests and the Cats have a history of being cautious in such matters.

Small forward Darcy Lang has been cleared of a fracture after he copped a kick to the shin when tackled in the third term on Sunday's clash.