The injury occurred in an innocuous incident as Rodan moved to take an uncontested mark during a training drill.
The 27-year-old had revolutionary LARS surgery on the same knee in December last year when he ruptured his anterior cruciate ligament in another pre-season mishap.
In a statement on portadelaidefc.com.au, the club said an arthroscope showed that the original LARS ligament was frayed and the surgeon decided to take a conservative approach and replace the ligament.
"Rodan is expected to undertake a similar rehabilitation program to his initial LARS procedure late last year," the statement said.
He made a remarkable return to the AFL this season, playing 19 games and showcasing all of his trademark speed and elusiveness.
It is Rodan's third major bout of knee surgery, with the former Richmond forward having had a traditional reconstruction after damaging his right knee in a pre-season match for the Tigers.
