Michael Lewis spoils during a NAB League match on July 10, 2021. Picture: AFL Photos

CARLTON will give young defender Michael Lewis the opportunity to trial for the last spot on the club's list over the next month, as its search for key defensive depth continues.

Lewis, who turns 20 later this year, joins forward-ruck Josh Cripps and fellow defender Tyreece Lieu in auditioning for a spot on the Blues' rookie list under pre-season Supplemental Selection Period (SSP) rules.

Lewis, a 192cm defender, played six games for the Sandringham Dragons as an over-age prospect throughout last year's NAB League season but was overlooked by clubs at the NAB AFL Draft.

He has already signed with Carlton's VFL team for the upcoming season and has joined in with the main group as a fill-in player for a series of match simulation drills, with the Blues moving to formalise his position as a train-on player over the weekend.

Along with Cripps and Lieu, Lewis has until March 9 to prove his case in the hope of filling the club's only remaining list vacancy under SSP rules. Carlton can also leave the position open for the NAB AFL Mid-Season Rookie Draft later in the year.

Josh Cripps in action at Carlton training on December 6, 2021. Picture: AFL Photos

The Blues are on the hunt for key defensive depth following the sudden and unexpected retirement of veteran defender Liam Jones late last year, after he failed to comply with the League's vaccination policy.

The club recruited Lewis Young from the Western Bulldogs during the Continental Tyres AFL Trade Period, while it has also shifted swingman Mitch McGovern into a defensive role across pre-season.