Getting Hogan's back injury right so that the 19-year-old can make his debut in "round 3 or 4" is now the best-case scenario for the Demons' medical staff.

Hogan has revealed the stress reaction in his lower back is still giving him significant pain, and given his long-term value to the club, it can be assumed Melbourne will take a cautious approach with its prized key forward so that return date could blow out even further.

It means the situation Paul Roos' team finds itself in leading into its season-opener against St Kilda on Saturday night - being without its best three key forwards - could be a short-term reality until round three.

That is when the Demons other key focal point, Chris Dawes, is expected to resume from a calf injury, however there is a chance he could be ready for the round two match-up against West Coast at the MCG.

Hogan was non-committal when asked about his back injury on Monday. "It's coming along well, but it's probably two to three weeks. That's at best," Hogan told Channel Seven's Talking Footy.

"At the moment, we still don't know. It's very symptomatic," he said. "There's no real time frame, hopefully round three or four, hopefully. But I'm not too sure."

That the Demons will be without its first-choice key forwards will come as a relief to St Kilda, given one of its key defenders, Sam Fisher, is in serious doubt for the game at Etihad Stadium because of back stiffness that has required an injection.

The 31-year-old's absence would mean Alan Richardson will take in an even less experienced team into his first game, with suspended midfield duo Leigh Montagna and Lenny Hayes already set to miss and last year's best and fairest winner Jack Steven out long-term with a foot injury.

Midfielder Luke Dunstan appears set to make his debut, while rookie midfielder Eli Templeton may also be elevated to the senior list after an impressive pre-season.

The club's first draft pick last year, Jack Billings, pushed his case strongly with a classy game in a VFL practice match on the weekend.