Patrick, 24, went down in a marking contest during a match simulation drill at Metricon Stadium.
Scans revealed a right hamstring injury but the full extent of the damage will not be known until Friday.
A lengthy injury would be a cruel blow for Patrick who was still buzzing from earning a one-year contract extension after the 2012 AFL season.
Patrick - recruited from Lajamanu in the Northern Territory - had just come back from a knee complaint that forced him to miss the last three weeks of the 2012 campaign.
