Gray went off with a knee injury which has now been confirmed as a medial ligament injury.
The Power confirmed in a statement that Gray would miss at least the next two months of football after he undergoes surgery.
"Gray was subbed out of the game at half time after tearing the medial ligament in his left knee, with scans revealing the severity of the injury was such that it would require surgical repair."
"This will see him sidelined for about eight weeks."
Port Adelaide also confirmed that defender Lachie Jones was set for another injury lay-off due to a hamstring injury.
"Defender Lachie Jones will also have a period on the sidelines after injuring his left hamstring in the win against the Suns," said the Power.
Embed from Getty Images
"He is expected to miss about a month of football."