Shojaei, 32, joined Panionios in July 2016 and was a key player for the Greek Super League team along with his fellow Karim Ansarifard.
Shojaei has caught the eye of Panathinaikos following a good performance at the Greek Super League.
Newly-appointed coach Marinos Ouzounidis is eager to sign the Iranian player.
Shojaei has played at Spanish club Osasuna from 2008 to 2013 and was a member of Las Palmas as well.
He has also played at Iranian clubs Saipa, Sanat Naft and Qatar’s Al-Shahania and Al-Gharafa.
Shojaei has made 68 appearances in Iran national football team and scored eight goals.