THE DOOR is ajar for Geelong rookie Zach Guthrie to make his AFL debut this Sunday with the Cats moving injured forward Cory Gregson to the long-term injury list.

Gregson, 20, has been battling a foot stress fracture since July last season.

The Cats are yet to name a senior list replacement for Gregson, but Guthrie has staked his claim for promotion with a promising pre-season.

The 18-year-old younger brother of Cats midfielder Cam impressed in two of the three JLT Community Series games.

He picked up 24 touches against Hawthorn and 18 versus Adelaide before missing the last game against Essendon after slightly hyperextending his knee.

The half-back then shone in a VFL practice match on Friday night against the Bombers with 15 disposals, four rebounds and six hard ball gets.

The scratch match saw three Guthrie brothers play together, with Cam racking up much-needed minutes after missing a chunk of the pre-season with a calf injury, and VFL-listed Josh also running out.

Zach Guthrie said he had been surprised to play with the seniors so soon after arriving at the club, and would embrace any chance to run out against Fremantle on Sunday night at Domain Stadium.

"I'd obviously love to play round one. That's been the goal since I did play in the first JLT game, so if I was lucky enough to get the opportunity, I'd be rapt," Guthrie told the Cats' website.

"If not, just look to go back and play the best footy I can in the VFL and hopefully, if possible, get a game later in the season."

Gregson has undergone two bouts of surgery on his navicular stress fracture since the middle of last year.

He had a procedure to reduce irritation from a screw in January this year, and has worn a moon boot since.

The Cats have a relatively short injury list and will have nearly a full complement of players to choose from for their trip west this weekend.

Mitch Duncan and Tom Stewart will be available after scans cleared them of hamstring injuries following the final round of pre-season games.

Stewart is in line to make his AFL debut along with draftee Brandan Parfitt, while former Carlton defender Zach Tuohy is expected to play his first game for the Cats.