Hassanein (pectoral) is likely to be out "for a while," Eric Woodyard of ESPN.com reports.
Lions coach Dan Campbell could not say definitively whether Hassanein would be able to play this season, per Woodyard. The sixth-round pick out of Boise State suffered the injury during Saturday's preseason game against the Dolphins. Prior to the setback, the edge rusher was fighting for a depth role.