Gardiner has recovered from shoulder surgery having not played since Round 3, while Marshall earns his first game back at AFL level since last year’s Grand Final.
The pair come in for Lincoln McCarthy who is out with hamstring awareness and defender Darragh Joyce who returns to the VFL.
Gardiner and Marshall are both named to start on the interchange with Kai Lohmann, Conor McKenna and Bruce Reville.
The Lions three emergencies are Joyce, James Tunstill and Shadeau Brain.
Thursday night’s Grand Final re-match against Geelong is scheduled for a 7:30pm start and will be broadcast live on Seven, Fox Footy and Kayo.