Former Crows and Bombers big man Shaun McKernan has signed a one-year deal with St Kilda.

Being an unrestricted free agent, the addition of the 30-year old costs the Saints nothing, who will help provide ruck support for Paddy Ryder and Rowan Marshall.

McKernan was let go by Essendonย in September to put an end to his six-year career at the club.

Saints Head of List Management James Gallagher said McKernan would be a valuable addition to the club.

โ€œWeโ€™re really pleased to have signed Shaun for next season,โ€ Gallagher told the club website.

โ€œOur structure in the ruck and key forward roles, having Paddy, Max and Rowan all available, was a real cornerstone of our game plan this year.

โ€œHis experience will also be a great asset to assist in the growth of our young list.โ€

McKernan has booted 72 goals from 87 AFL games, crossing from the Crows to the Bombers at the end of the 2014 season.

AFL free agency closes today.