Keeffe is keen to play on next year at another club, with several inquiring about his avaiability if he became a delisted free agent in recent weeks.
The hard-running full back played 40 games until serving a two-year drug ban.
The 27-year-old played as a forward in the VFL all year and did not get a senior game.
But he remains thankful the Pies rookie-listed him last year and then gave him another chance this season.
He and good mate Josh Thomas, who has signed a one-year extension, tested positive to the banned substance clenbuterol in February 2015.
They served two-year bans but were rookie-listed by the Pies late in 2015 with the understanding they could not play in 2016.
The 204cm defender played 40 games with the Pies as an athletic key defender