The Warrior actor is said to be in talks with Warner Bros to join the cast of the upcoming prequel.
Edgerton is tipped to play legendary Greek general Themistocles in the follow-up to Zack Snyder's 2006 war picture, Vulture reports.
Watch the trailer for 300 below:
Edgerton is currently starring in the prequel to John Carpenter horror The Thing and will next be seen in an adaptation of The Great Gatsby.
Gerard Butler and Lena Headey are believed to have signed a deal to reprise their 300 roles.
Battle of Artemisia producer Mark Canton this week praised the "highly intelligent, epic story" turned out by Snyder and screenwriter Kurt Johnstad.
300: Battle of Artemisia, directed by Noam Murro, is yet to be given a release date.
> Gerard Butler: '300 was my favourite role'
Watch Digital Spy's recent interview with Joel Edgerton and his Warrior co-star Tom Hardy below: