The 21-year-old is expected to be sidelined for up to five months, which means he will not be available for senior selection until the last few rounds of the season.

He suffered a stress reaction in a ligament across the top of his foot in December and, after consulting his surgeon a fortnight ago, it was decided that an operation was the best course of action.

It is the latest setback for McCarthy, whose fledgling career has been curtailed by foot and back problems.

Since being drafted by the Cats in 2011, the young Cat has managed just five games in three seasons – including last year's semi-final loss to North Melbourne.

Geelong football manager Steve Hocking told the K-Rock Football website that McCarthy was suffering "corrosion" in the area where the leg bones join the foot.

"It's like a flap that's hanging within that cartilage," Hocking said.

"What they have to do is get in there and irritate that cartilage, and that generates blood flow and regenerates it.

"The lack of blood flow into that region is a real concern for anyone who suffers from a fracture within that bone."

Hocking insisted McCarthy was remaining headstrong despite having missed the 2013 season due to a navicular bone injury in his foot and being sidelined for 12 weeks last year as a result of a back complaint.

"He'll work his way through it and we've got systems in place that will support him accordingly," Hocking said.

"He's got a contract to run for next year, so that's not a concern for him either."