After an injury-interrupted campaign last year, Renouf was delisted but re-drafted as a rookie, only for a ruptured patella tendon to prematurely end his 2014 season.
Heath has also been forced to endure wretched luck, first at the Sydney Swans where he underwent two knee reconstructions and then this year, when he suffered a third ruptured ACL.
He underwent LARS surgery and played in Port's losing SANFL grand final last weekend.
Injuries also restricted Hitchcock to just nine SANFL games this year, including the grand final.
He played 35 games for the Power, while Renouf and Heath played 16 (68 total) and 12 (14 total).
Coach Ken Hinkley said the trio would always be considered a part of the Port family.
“We wish them all the best for their futures and I’d like to thank the boys for their hard work and commitment to the club,” he said.
“It’s always tough when people leave the club but unfortunately these are the decisions that have to be made this time of year.