The delistings follow the retirements of three of its veterans (Jason Blake, Justin Koschitzke and Stephen Milne) and the resignation of club CEO Michael Nettlefold.
Ledger, 21, played eight career games with the Saints - just the two in 2013 - while Lever, 20, and Staley, 20, failed to appear in the senior team.
Saints head of football Chris Pelchen said delistings were part of the AFL landscape.
"This is a difficult time of year with changes being made to player lists at all AFL clubs. We would like to thank Tom, Jay and Jordan for their contributions to the St Kilda FC and wish them every success for the future," Pelchen said in a statement.
The Saints have now made six changes to the club's list in preparation for the upcoming trade and draft periods.
Click here for all the retirements and delistings