IN-FORM Melbourne defender-turned-forward Harrison Petty faces a "bit of time" on the sidelines after suffering a leg injury in his side's 32-point comeback win over stragglers North Melbourne.

Petty left the field in the third term and was later in a moon boot after his ankle got caught in a tackle on Sunday at Blundstone Arena.

The 23-year-old had slotted two goals, coming off a career-best six last round against Richmond.

"It’s a bit of a concern for us. He’s got a mid-foot injury. We’re not 100 per cent sure what it is," Melbourne coach Simon Goodwin said post-game.

"Fingers are crossed but it’s looking like he could be out for a bit of time. We’ve got to get it assessed.

"He had a similar type of injury earlier in the year. It’s probably not looking short-term at the moment."

It is a sizeable blow with finals fast approaching for the high-flying Demons, who overcame a sluggish start to notch their fifth win in a row.

Petty's injury could open the door for the recall of high-profile recruit Brodie Grundy, who was dropped to the VFL a few weeks ago.

KANGAROOS v DEMONS Full match coverage and stats

It was a less-than-ideal welcome back for North coach Alastair Clarkson, who returned to the helm for the first time since stepping away from footy in round nine, but the veteran coach was pleased with his side's effort.

"Last time we played them they made us not even look second-rate, perhaps even third or fourth-rate," Clarkson said post-game.

"We're learning. We played a really, really good side and for 40 minutes of footy we really troubled them, so that was pleasing.

"We've just got to find ways to do it for longer."

Clarkson coached his 400th game against the Dees, but said the milestone was overshadowed by his excitement to be back at North Melbourne.

"Not as yet, that’ll probably come at another time," he said.

"My excitement was not so much a milestone, just getting back amongst the group.

"We’ve got a lot of work to do, but we knew that from the get-go. That’s the exciting part of the journey. There is no silver bullet to this.

"(People) will just look at the fact we haven't won any more games than we did last year.

"We're making progress and hopefully that'll translate into some more wins, certainly next year.

"We've got three more rounds to go and still a lot to get out of the season."