Marshall was initially taken from the ground after some friendly fire by teammate and fellow Port forward, Mitch Georgiades.
Georgiades’ knee collected Todd in the back of the head and neck area during a marking contest early in the game.
He passed that concussion test on the bench, but after the game Port Power doctors and medical staff had placed Todd under concussion protocol.
Todd spent less than 40 per cent of the games duration on the field.
Due to concussion protocol, Marshall will be ruled out for at least the next 12 days.
It will mean missing the clash with the Sydney Swans.
This concussion protocol is his fifth in as many as three seasons.
Port’s chief executive Matthew Richardson spoke with media on the Saturday.
When asked if he thought Marshall should retire, he replied "it's certainly too early for that".
"Clearly it's concerning. We always take a really cautious approach with these things,“ he said.
“I’m disappointed for Todd; I thought he was terrific early last night as well, and played a really important role.
"Our medical guys will do everything they can to make sure we look after his health and wellbeing."
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