Officers have already made contact with Steven and will attempt to speak to him again later on Sunday.

The incident on Saturday night was referred to police by hospital staff after the Cats player checked-in for medical attention.

"Stonnington Crime Investigation Unit detectives are investigating after a 30-year-old Lorne man presented at a Melbourne hospital overnight with a non-life-threatening injury," a Victoria Police spokesperson said.

"Detectives are investigating the circumstances surrounding the incident and hope to speak to the victim again later today."

The Cats earlier on Sunday released a statement confirming an incident had taken place.

"Jack is in hospital and recovering. The club's concern is for Jack's health and well being," a Geelong spokesman said.

"The matter has been referred to police and until their investigations are completed the club will not be in position to offer further comment."

Former Geelong captain Cameron Ling, who skippered the club to the 2011 premiership, told ABC Radio: "The injury is certainly serious but not life threatening which is good news.

"But a really serious incident that Jack's been involved in and we hope he's OK.

"At his best he is a wonderful footballer, and he came to the Cats looking for a change of scenery to reinvigorate his love of the game.

"He was excited about what the season held for him. We don't know many details other than that footy is the furthest thing from his and his family's mind."

The 30-year-old Steven was traded to the Cats last October after a decorated 183-game career with St Kilda, where he won four best-and-fairest awards.

Steven did not play in Geelong's round one loss against GWS in March before the AFL season was suspended.

He came close to AFL retirement last year as he dealt with mental health issues, playing just seven games in 2019.

His parents and extended family live near Geelong and that prompted the player's desire to be traded to the Cats.

"I will just be nice and comfortable ... get fit again, get happy, get healthy, that's just what I'm aiming to do," Steven said last October after signing with Geelong.

Australian Associated Press