Okposo will make his Panthers debut Tuesday on the road against Dallas, Jameson Olive of the Panthers' official site.
Okposo played 61 games with Buffalo this season, recording 12 goals and 10 assists. The 35-year-old will be on the third line with Anton Lundell and Eetu Luostarinen. The veteran Okposo should also see minutes with the man advantage after averaging 1:17 of power-play ice time with the Sabres.