The 24-year-old spent last season on loan at Championship side Crystal Palace and The Eagles had an option on the player to make his move permanent.
However, Fonte's agent, Artur Teixeira, has said that should Palace opt to not make the playerâ€™s stay at Selhurst Park a long-term arrangement then Portsmouth would be eager to discuss the possibility of the one-time Sporting man moving to Fratton Park.
"The coach of Portsmouth has contacted me to say that if Crystal Palace do not execute the option of the sale of the player to them, then they are interested in him," Teixeira told Portuguese daily Record.
"For Fonte the chance of Premier League and Uefa Cup football with Portsmouth would be sensational."
Neil Warnock has until June 30 to register his interest in turning Fonteâ€™s stay in South London into a permanent one.