Borussia Dortmund is monitoring the goalkeeper market to be prepared for any future eventualities. In this context, the club is observing Olympiacos Piraeus's Greek goalkeeper Konstantinos Tzolakis. According to the Greek newspaper 'Fos', Dortmund scouts were in attendance for the 23-year-old's match against Real Madrid on Wednesday, which ended in a 3-4 defeat for his team. The newspaper also reports that further scouting visits are expected in the coming weeks. Tzolakis, who has been watched by Bayer Leverkusen in the past, has a contract until 2027, which could potentially make him available for an affordable fee next summer. The goalkeeper, who joined Olympiacos in July 2019, has made 11 appearances in the league this season and has 7 caps for Greece; his market value is estimated by Transfermarkt at €13.00m.