MELBOURNE will be without promising recruit Sam Frost for at least a month after scans revealed he has a broken toe.

The 21-year-old hurt his left toe during the second quarter of Saturday’s 25-point loss to Adelaide. He was immediately subbed out of the game.  

Melbourne football manager Josh Mahoney said a scan had identified a small crack in the bottom of Frost's toe.

"At this stage, it’ll be a four-to-six week injury," Mahoney said. 

Coach Paul Roos also provided a further update at his press conference on Monday afternoon. 

"It's a crack in the second metatarsal, which is obviously really disappointing," Roos said. 

"It looks like every team is going through a few injury worries at the moment but you've just got to cope with them unfortunately." 

Frost crossed to the Demons during last year's trade period after 21 games with Greater Western Sydney and had impressed up forward and in a back-up ruck role in the first three games of the season.

Frost's injury has left Roos with several selection issues to contemplate as reshuffles the team ahead of Friday night's clash with Richmond. 

The second-ruck options are likely to come from Max Gawn or Cameron Pedersen, or the Demons may decide to keep the side settled and deploy Chris Dawes in the back-up ruck role, as he did against the Crows on Saturday. 

"Dawesy went into the ruck (against the Crows). It's probably something he hasn't done all that often and we thought he embraced that role reasonably well," Roos said. 

"Casey (Scorpions) had a really good win on the weekend which is a chance to have a look at that role. It's always a tough one – that second ruck role because they need to play a fair bit forward.

"We'll have a good look at that and assess what we think we can do."

Roos also touched on the progress of former co-captain Jack Grimes, who is yet to break into Melbourne's side this season. 

He said Grimes was working extremely hard in the VFL to earn his spot back. 

"He's really supportive of the coaching group and he's really supportive of the players going out on to the field," Roos said. 

"He knows he needs to work on some things, but he's really putting the club first which I really like."