Veteran Geelong midfielder Cam Guthrie sustained a quad injury during the opening minute of the Cats' match simulation against Carlton on Thursday morning.

Guthrie was helped from the Princes Park surface by Cats medical staff only six seconds into the match.

While Geelong is yet to provide a prognosis and a timeline, Thursday's injury proved another for the senior midfielder who struggled last year with a toe injury and only managed to play six games.

Guthrie has played 236 games and is a key asset in helping the growth of the young midfield at the Cats.

Geelong assistant coach James Rahilly spoke after the match and said it's hard to tell the extent of the injury yet.

"It's a quad, but we don't know the severity of it. But it's his quad area," Rahilly told AFL Media.

"I haven't seen him … he was over the other side. But I'm sure they'll look at it. We'll see what comes of it, but he's had a ripping pre-season. He hasn't missed a trick, so we'll see how it plays out."

Besides Guthrie's injury today, the Cats' list is at full fitness and strength with only one player who was not notably listed to play at Ikon Park, with Gary Rohan managed.

Geelong will open its 2024 campaign proper when they take on St Kilda on Saturday, March 16.