Evangelos Marinakis has been busy working on deals to strengthen Nuno Espirito Santo's squad in recent weeks ahead of the Tricky Trees' return to Europe this season.
They've reportedly now focused their search on recruiting a right back, with Cash one of the names on Forest's list.
Club officials have contacted Aston Villa over a potential move for the 28-year-old Poland international, but negotiations are still at an early stage.
Forest have also made an offer to Sevilla for right-back Jose Angel Carmosa, 23.
A product of the club's academy, Carmosa made 35 LaLiga appearances for Los Nervionenses last season.