ST KILDA'S Shaun McKernan has called time on an AFL career spanning 13 seasons across three clubs.

The 31-year-old informed teammates of his decision on Tuesday after a 12-month stint at Moorabbin as a back-up ruck/forward having not been offered a new deal for 2022.. 

Recruited as a delisted free agent after being cut by Essendon at the end of 2020, McKernan managed four matches for the Saints before he was hampered by a toe injury in the second half of the season. 

McKernan previously played 34 games for Adelaide (2009-14) and 53 matches for the Bombers (2015-2020) taking his career tally to 91 games. 

Shaun McKernan when he was an Adelaide Crow back in 2011. Picture: AFL Photos

After a finals finish in 2020, the Saints targeted McKernan to provide readymade depth behind Paddy Ryder and Rowan Marshall, eyeing a premiership tilt in 2021. 

Both Ryder (personal sreasons) and Marshall (foot) missed the Saints' season opener against GWS, paving the way for McKernan to ruck alongside summer rookie signing Paul Hunter. 

McKernan played the opening three matches before Marshall returned with the ex-Bomber and Crow featuring once more in round 10 against the Western Bulldogs. 

WHO'S CALLED IT QUITS 2021's retirements and delistings

His career highlight came in 2019 for Essendon with a four-goal performance in a come-from-behind win against Gold Coast in round 19 that netted three Brownlow Medal votes and helped the Bombers to the finals. 

Shaun McKernan running hot against the Suns in 2019. Picture: Getty Images

His departure from the Saints will enhance Hunter's chances of a new deal with Ryder expected to soon sign an extension for 2022. 

Other Saints out of contract include free agents Jack Billings, Luke Dunstan and Seb Ross, plus Jake Carlisle, James Frawley, Jack Lonie and Mason Wood. 

Co-captain Jarryn Geary is closing in on a fresh one-year deal.