PAUL Roos believes Christian Petracca has learned his lesson after copping a blast from his coach when the untried Demon broke a toe trying to dunk a basketball during the Christmas break.

The No.2 overall draft pick in 2014 missed the entire 2015 season after rupturing his ACL in February last year, and then took another six weeks to recover from the break suffered over the Christmas break.

Roos said he was trying to teach the young Demons – including Petracca and star forward Jesse Hogan – elite habits that would prolong their careers.

Brayshaw shakes off knee injury to shine in VFL

"It was pretty blunt. Discussion is the wrong way to put it. It wasn't a discussion," Roos told News Corp of his confrontation with Petracca.

"He was trying to dunk the basketball in his backyard. If it's Tommy McDonald, you say 'why did you do it?' 

"If it's Christian, it's another layer because of his knee. It's put him out for six weeks and robbed the club of a player for round one.

"He had the hangdog look for a couple of days then bounced back. But he looks like he's learned his lesson and maybe that's a good thing."

Petracca is expected to return to match practice within two weeks.

Roos said Hogan must not cut corners if he wants to succeed over the long haul.

The hulking forward has endured a roller-coaster start to his career with Melbourne, winning VFL affiliate Casey Scorpions' best and fairest award as a teenager in 2013 before he was eligible to play AFL, then playing just one VFL game in a 2014 season ruined by a back injury.

He rebounded to make an instant impact in his first senior season, kicking 44 goals from 20 games to win the NAB AFL Rising Star in 2015.

"He's a terrific young man and he's not arrogant at all," Roos said.

"He still needs to get really good at AFL habits. It's teaching young guys that the weights sessions is equally as important as the main training session or meeting.

"That's not exclusive to Jesse. It's (Angus) Brayshaw and Petracca and (Sam) Weideman."