A €30 million deal? BVB reportedly has a major transfer surprise "in the pipeline"

According to the former centre-back, several Bundesliga clubs are tracking the Polish Under-21 international, who currently plays for Mainz 05. "According to my sources, several German clubs already have Kacper on their radar – such as Leverkusen and Dortmund. But clubs from England and Italy are also interested in him," Hajto told the Allgemeine Zeitung. As early as the beginning of March, Turkish transfer journalist Ekrem Konur had linked Potulski with BVB.

The only sticking point in the 18-year-old centre-back's development is his recent lack of playing time, which, according to kicker, has already annoyed his father, Bartosz. Since early March, Potulski has sat on the bench for 90 minutes in five of Mainz's seven Bundesliga matches, starting just once.

"I see huge potential in Kacper Potulski. Mainz could eventually command €30 million for him, but for that to happen, he needs to play," the 53-year-old added.

Potulski earned his first-team debut for Rheinhessen in November under the since-sacked manager Bo Henriksen and quickly secured a regular spot under Urs Fischer after impressing with a debut goal against FC Bayern in mid-December. 

Yet he has since slipped out of the first team, and the fallout is clear: for the second time in 12 months he has switched agents, now linking with Sports360. Is a transfer looming? "The lad might soon ask himself why he should stay in Mainz if he plays brilliantly one moment and then not at all the next. That's a danger," Hajto warned of wider consequences for Mainz. "Kacper has always made the most of his chances and put in strong performances. He came on in Hoffenheim and played superbly. I don't understand why he hasn't played a part since that match."

Despite the simmering discontent, sporting director Niko Bungert insists Potulski remains central to Mainz's future, pointing to his contract that runs until 2028: "Kacper is the future. He has incredible quality and will be a regular on the pitch for us. I'm certain of that."

A move to BVB this summer would likely come far too soon. With Niklas Süle having left, Emre Can sidelined by a serious injury, and the possibility that defensive stalwart Nico Schlotterbeck could still depart via his release clause, the Black and Yellows are unlikely to stand pat and will be looking to strengthen their central defence. However, Potulski is unlikely to match their requirements at this stage.

Most recently, RTL/ntv and transfer insider Fabrizio Romano both reported interest in Union Berlin centre-back Danilho Doekhi. His contract expires this summer, and the 27-year-old offers both a goal-scoring threat (seven goals in 34 competitive appearances) and established Bundesliga experience.