UNLUCKY Cat Lincoln McCarthy will have surgery on his left foot in Sydney on Tuesday.

The injury is expected keep him sidelined for five months. 

The talented McCarthy, who has played just five games since his debut in 2012, had trouble with his foot pre-Christmas, but it was the recurrence of an old injury that has led to surgery. 

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Cats' football manager Steve Hocking told K-Rock Football the 21-year-old needed the operation to generate blood flow back into the foot.

"It’s the cartilage that lines the joint where your leg bones come down and your foot actually joins in,” Hocking said.

"He’s got some corrosion in the area. It’s like a flap that’s hanging within that cartilage.

"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."

"For us it is really about his long-term wellbeing. That is the important part at this stage," Hocking told AFL.com.au a fortnight ago.

Hocking said McCarthy was a resilient youngster and the Cats were confident it had systems in place to support him. McCarthy was also contracted until the end of 2016, so had time to get his body right.

The Cats escaped the opening NAB Challenge game against the Suns in Townsville unscathed and have a relatively slim injury list at this stage.