Trabelsi, who plays his club football for Ajax but is available on a Bosman, is a right sided midfielder. Rafael Benitez has declared an interest in the Tunisian after losing patience with Sevilla over Daniel Alves.
Sevilla are refusing to budge on their £12m valuation of Sevilla so Benitez has turned his attention elsewhere. Trabelsi played in all three of Tunisia's games at the World Cup.
Signing Trabelsi on a free instead of Alves could free up money for a bid for Feyenoord's Dirk Kuyt.