Ongoing speculation over Carlton star Patrick Cripps' fitness won't lull ladder-leaders Melbourne into a false sense of security heading into Sunday's clash at the MCG.

The Blues this week played down concerns over their captain after The Age reported Cripps has been playing with a fracture in his back.

The report came with the 26-year-old contest specialist struggling to have his usual impact this season despite playing all eight matches so far.

But the unbeaten Demons are preparing to encounter Cripps at his best as they attempt to extend their winning streak to nine matches against an unpredictable Carlton (3-5) side.

"I know what he's capable of," Melbourne coach Simon Goodwin said. "He's a player that can change momentum in games and have a huge impact and win games.

"We've got the utmost respect for him, there's no question about that. He's not in the best form that he would like to be in, I'm sure, but he's not that far (off it) either.

"This game's a funny game and a quality player like Patrick will get the respect that he deserves. We'll be ready for his best."

Goodwin has also got his sights on Harry McKay after the Carlton spearhead's hot start to the season.

McKay entered round nine leading the Coleman Medal race with 30 goals, including 14 majors in the last three weeks and five hauls of four or more.

The 204cm target man presents a big challenge for Melbourne defender Steven May, with both players in All-Australian form.

May has enjoyed a superb start as the central figure in the Demons' competition-best defence and shut down Sydney superstar Lance Franklin last week.

"(McKay) really has become one of the premier forwards of the competition," Goodwin said.

"Steven May has done some really strong jobs for us in the past against various oppositions and I'm sure (McKay) is one player that he's looking forward to playing on.

"We're going to have to be really mindful of him and he certainly is one of the more targeted players in the AFL in terms of ball going inside 50, so he's certainly a big part of our planning."

Emerging key forward Sam Weideman will play his first match of the season for Melbourne alongside Ben Brown and Tom McDonald in attack.

Young ruck-forward Luke Jackson's finger injury opened the door for Weideman and means Dees skipper Max Gawn will shoulder the bulk of the ruck load against Carlton's Marc Pittonet.

The Blues have regained former captain Marc Murphy, who returns from a neck injury, with Will Setterfield and Nic Newman also called up.

Jack Silvagni is out because of concussion, while Jack Newnes, Michael Gibbons and Sam Petrevski-Seton have been dropped.