MELBOURNE is sweating on the severity of a calf injury to superstar midfielder Christian Petracca and the Match Review findings following a late James Harmes bump having limped to a disappointing qualifying final defeat to Sydney on Friday night.

Petracca spent the majority of the game severely hampered by a calf contusion, having collided with Sydney great Lance Franklin while attempting a smother midway through the first quarter.

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The reigning Norm Smith Medal winner hobbled away from the contest and spent a significant portion of the quarter-time break receiving treatment from medical officials, but played out the game despite being heavily impeded.

The Demons will assess the extent of the injury in the coming days, but remain hopeful that the gun onballer will be fit to play against Brisbane in a do-or-die semi-final clash next weekend.

"He got a pretty significant kick from Buddy just below the knee in the calf. He's just got a contusion that we'll assess through the week, but he was pretty sore," Melbourne coach Simon Goodwin said afterwards.

"Clearly, it limited his movement for the majority of the night. It had a bit of an impact on his game. But he'll get that right, reset and hopefully be all-clear and ready to go next week."

Harmes could also find himself in doubt for next weekend's must-win clash against the Lions, having floored Swans defender Jake Lloyd with a brutal late collision in the early stages of the final quarter.

Harmes was reported by the on-field umpire for rough conduct, having appeared to catch Lloyd with a forearm to the chest/throat area, giving away a 50m penalty which resulted in a crucial Swans goal that extended their lead to 18 points.

Goodwin said afterwards that it was his belief Harmes made contact with Lloyd's chest, therefore shouldn't be in trouble with the Match Review Officer, whose findings will be released on Saturday.

"It was clearly a collision," Goodwin said.

"But, from what I've seen, he gets him in the chest. He played on with no concussion. They got a 50m penalty, which cost us a goal. It's one of those collisions in footy that happens. It was a little bit late, but he got him in the chest. Hopefully, we move forward as a competition."

Melbourne conceded eight of the final 10 goals to slump to a 22-point loss, with its forward line failing to capitalise on its midfield winning six more inside 50s over the course of the contest.

It could put key forward Tom McDonald back in the frame to play in next weekend's semi-final, having returned from more than three months on the sidelines due to an ankle injury in the VFL last week.

"They (the club's VFL side) have got a big session tomorrow," Goodwin said.

"We'll assess that throughout the week, but that's something we're not thinking about right at the moment.

"We'll see how he trains tomorrow. He was still a fair way off last week, so we'll see how he trains and we'll see how the team goes once we get it assessed. We're certainly not going to make a decision on it tonight."

There was drama before the match, with important forward Bayley Fritsch missing the national anthem and pre-game addresses having felt at his knee before going back to the rooms with the club's medical team.

But he soon returned to the field just before the bounce, ultimately proving one of Melbourne's better players with three goals and five score involvements from 13 disposals and six marks.

"He had a bit of a funny feeling in his knee in the warm-up," Goodwin said.

"He went down and got assessed, felt fine and came out. He had no issue. He played pretty well. I'm glad we had him out there."

Melbourne secured three convincing victories throughout last year's finals campaign on its way to a drought-breaking premiership win, but will have to take a different route this season after its qualifying final loss on Friday night.

However, ahead of a semi-final against Brisbane next weekend, Goodwin said the side's challenge remained the same and contended that the Demons must win three finals matches regardless of when they come to secure the flag.

"Our situation and our scenario hasn't changed," Goodwin said.

"Any team in the competition has got to win three games in a row to win it. That's no different for us. Our challenge is to do it next week and get that first win away, against Brisbane who played a fantastic game last night.

"The equation for us hasn't changed. That's why you get the double chance. But we've got to be really clear as a club that we need to learn from what we did tonight, get the basics of our game right that will stand up in finals footy, execute better when we get our chances, and be more disciplined.

"That's the key to the game. Do the basics well and give yourself a chance."