The outstanding youngster suffered the injury during the NAB Challenge series.
Last week, his length of time on the sidelines was increased to six weeks, due to bone stress in his left patella.
The club is continuing to take a cautious approach with Scully's rehabilitation.
Scully is now on target for a return at the start of June.
But fellow midfielder Jordie McKenzie is getting closer to returning from a groin injury.
McKenzie is now just three weeks away, after missing the start of the season.
And 2008 Hawthorn premiership ruckman and first-year Melbourne rookie Robbie Campbell (achilles) is now a month from playing.
Melbourne injury list: round five