Geelong will be without key forward Mitch Clark for their round-one AFL blockbuster against Hawthorn thanks to another injury setback.

The calf injury he suffered in January has flared again and the Cats are uncertain about when he will return.

“This is frustrating for Mitch and for the club, but we expect that he will continue to rehab the injury and be available early in the season,” Cats football manager Steve Hocking said.

“Mitch has had a solid pre-season and has put a lot of work in through the summer.

“His recovery was on track before this setback and he will continue to work hard to get back on the field with his teammates.”

Clark has a history of soft-tissue injuries through his AFL career.

After retiring from the AFL in 2014, he returned last year with the Cats.

But Clark only managed eight games before a separate calf injury put him out of action for the rest of the season.