The 22-year-old had scans on Monday to assess the extent of the injury he suffered in the second quarter.
Melbourne Football Manager Josh Mahoney said Wagner will miss the rest of the JLT Series.
“It’ll (the swelling in the leg) probably take a week to settle down and then he’ll start running after that,” Mahoney told AFL.com.au.
“At this stage, we think it’s about a four- to six-week injury.”
The dislocation to Wagner’s leg occurred after his right foot got stuck in the ground when he attempted to tackle Bulldogs midfielder Luke Dahlhaus.
By all reports Wagner had been impressing in the pre-season for the Dees and was firming as a round one starter.
The former rookie played 14 games for Melbourne in his first season, averaging 17.6 disposals, and was elevated to the team’s senior list with a new-two year deal as reward.