EMERGING Melbourne star Christian Petracca has shaved 10 seconds off his personal best time trial effort as he prepares for more midfield time in 2018. 

Petracca has spent this pre-season training with the club's midfielders, getting a feel for the required positioning at stoppages and the role he needs to play within the Demons' setup. 

Boosting his endurance was a clear emphasis for the 22-year-old during his off-season and again on his return to the club in November.

Petracca will still play long periods of the game as a forward, but he is keen to add that versatility to his game.

"I have improved my running a lot," Petracca told AFL.com.au on Monday.

"That was my biggest focus throughout the off-season and pre-season.

"I'm always going to have that as something I need to improve on and so far I have knocked a lot off my time, and I'm looking for more." 

Gone are the days when Petracca was battling to keep up in running drills, as was the case when vision emerged of him towards the back of the pack in his first few weeks at the club after being selected with pick No.2 in the 2014 NAB AFL Draft.

That vision of his head wobbling and feet trudging became a running joke among his teammates.

However, now going into his fourth season, Petracca has flipped the script and was clearly one of the strongest performers during the shuttle runs the players completed in hot conditions last Friday. 

"I could always compete in games and sessions but it's more about getting from contest to contest at a good pace and not getting there and being stuffed," Petracca said. 

"Now I'm getting there and being quite fresh and feeling good."

He had a slight interruption where he was placed into the rehab group for a week after sustaining a slight strain in his quad, but he is back to full health and ready for the pre-season games ahead.

The youngster enjoyed the best season of his career in 2017, averaging 18.8 disposals and a tick over a goal a game from his 22 appearances. 

Petracca is being tipped by many pundits to have a breakout season and he said the onus was on him, reigning best and fairest winner Clayton Oliver, smooth-moving half-back Christian Salem and the other young players to steer the ship in 2018. 

With 39 games under his belt and at just 22, with the type of athletic prowess he possesses, Petracca appears well placed to make a quantum leap.