Celtic are reportedly interested in signing Portuguese right-back Aurelio Buta.
According to Fabrizio Romano, the Hoops want to strengthen their full-back positions before the new season begins, and Brandon Soppy is also on their wish list.
Celtic looked vulnerable at the back last season and will have to improve if they want to challenge Rangers for the league title next year.
Ange Postecoglou will be hoping to bring in the necessary defensive reinforcements before the window shuts, and the Royal Antwerp star could prove to be a quality long-term investment.
Celtic are looking for a new right back after agreement completed to sign Carl Starfelt as centre back from Rubin Kazan.