The Oilers acquired the 34-year-old centre from Florida for a fourth-round pick in this year's draft.
Smithson has three goals and two assists in 35 games for the Panthers, his third NHL team after turns with Los Angeles and Nashville.
The former Calgary Hitmen player has 38 goals, 57 assists and 352 penalty minutes in 578 career regular season games.
In the last five seasons, his face-off success rate has been between 54 and 59 per cent. During that same span, Edmonton has been the worst face-off team in the NHL.