FOUR-TIME St Kilda best and fairest Jack Steven will be out indefinitely as he battles a mental health and wellbeing issue.

He won't play in Saturday afternoon's clash with Greater Western Sydney at UNSW Canberra Oval.

FULL FIXTURE Every round, every game

Steven took part in full training during Thursday's session at RSEA Park.

Football manager Simon Lethlean told he didn't know how long Steven would be out for.

WHO MAKES FINALS? Do the 2019 Ladder Predictor

"The club and Jack have been working on managing his health and wellbeing over many months," Lethlean said.

"The best option at present for Jack to fully overcome his challenges is to take an extended break away from football.

"We don't have an exact timeframe on how long that will be, but the club will continue to provide as much support as possible.

"We ask again that Jack be given the time and privacy to deal with this matter."

Find AFL Exchange on Apple Podcasts, Google Podcasts and Spotify.

In late February, Steven took a mental health break from the club but returned to training and lined up in the Saints' opening two games of the season. 

St Kilda then said he was managed for the round three loss to Fremantle, saving him the trip west after a limited preparation.

MID-SEASON DRAFT 50 players who could spark up your list

However, the 29-year-old was absent the following week as well, in a win over Hawthorn.

Steven returned for round five against Melbourne, and featured in last week's defeat to Adelaide. 

He is averaging 21 disposals and six clearances per game in 2019. Steven spent plenty of time up forward earlier on in the campaign, due to his restricted pre-season.