Lycett, who underwent a PCL reconstruction in September last year after he hobbled off early in the second term of the elimination final loss to the Western Bulldogs, returned to the field for East Perth in a WAFL practice match on Saturday with the aim of being ready for senior football in time for round one.
However, the 24-year-old now appears likely to miss the opening round after suffering a dislocated left shoulder while laying a tackle.
The big man was taken from the field and treated at the ground, before leaving to have scans.
The club is awaiting the result of the scans to determine the full extent of the injury.
It is a huge blow for the Eagles, with Nic Naitanui already out for the majority if not all of the season with an ACL injury.