JACK Fitzpatrick and Cam Pedersen loom as two unlikely keys for Melbourne as they try to kick a winning score in their season opener against St Kilda.

The Demons will be without key forwards Mitch Clark, Jesse Hogan and Chris Dawes for Saturday night's Etihad Stadium clash.

Just as the Saints will have a badly-depleted midfield, Melbourne will have to somehow manufacture scoring chances.

Jeremy Howe will be their main forward and Demons co-captain Jack Grimes said on Wednesday that Fitzpatrick and Pedersen would also have important roles. 

"We're not expecting those guys to go out and kick your bags of five and six goals," Grimes told SEN.

"We're just expecting them to compete, bring a contest - even just bring the ball to ground and give the other forwards a chance."

Grimes added small forwards such as newcomer Jay Kennedy-Harris, who has been impressive in the pre-season, and Shannon Byrnes would be critical as they wait for their main key forwards to return.

"We do have a lot of exciting small forwards," Grimes said.

Clark is battling a foot injury and last week was given indefinite time off to deal with health issues.

Grimes said he had offered his team-mate help, but is also mindful that Clark needs time away from the club.

"It's tough - it's not just like an injury where the injury is going to be right and you're fine," Grimes said.

"Obviously we'd love to have him out there (playing), but at this stage we couldn't care less if he's not out on the track.

"We just really want to get him right ... we are worried for him.

"He just needs some space and time to sort through some things."

The absence of Clark, Dawes and Hogan for the start of the season adds to the uncertainty about Melbourne's fortunes under new coach Paul Roos.

Grimes said one of the most surprising aspects of Roos' coaching so far is that he has not tried to teach them anything radically different.

"Having someone like Roosy come in and all the other assistant coaches, probably the players were expecting him to do something really, really different and really unique, that's got his teams to the top before," Grimes.

"(But) it's probably been more the things he emphasises ... a lot of the little things around our game.

"A lot of it is based around the defensive side of our game, but just those little things he really drills into the team, non-negotiables.