The Bombers skipper failed to train with the main group on Wednesday, instead standing on the sidelines playing with a soccer ball and signing autographs.
Essendon coach John Worsfold said in his press conference that Heppell would need to get through training to have any chance of lining up against the Kangaroos.
“Obviously, there’s a process he has to undertake but we hope he’ll be ready to go,” Worsfold said in his press conference.
“In terms of selection for this week, [it is an important session]. Depending how he goes, if it was really sore we’d probably rule him out today, but if it’s still progressing, then we may give him an extra couple of days.
“We won’t know until we see what he does today.”
Defender Michael Hurley is also in doubt after having scans on his hip earlier in the week, despite Worsfold suggesting the 29-year-old would play.