Hossa was tripped by Islanders defenceman Freddy Meyer and slid into the boards behind the New York goal.
After remaining on his back for several minutes, Hossa got up slowly and was helped to the Atlanta bench. He went straight to the locker room for treatment, hobbling noticeably as he went down the tunnel.
Hossa represented the Thrashers in the All-Star Game at Dallas this week. He came into Friday tied for the NHL lead with 30 goals and ranked sixth in points with 63.