Mainz centre-back Kacper Potulski is a primary target for Borussia Dortmund. The process to sign the Polish youth international has started, and staying in the Bundesliga is a more realistic scenario than a previously discussed move to the Premier League. Dortmund faces competition from Bayer Leverkusen, while Bayern Munich, VfB Stuttgart, and Hoffenheim are also monitoring the situation. According to unofficial reports, the transfer fee could be between 15 and 25 million euros.