Borrusia Dortmund: 8 Possible Signings this Summer

#2 Niklas Stark (Hertha BSC)

Niklas Stark applauds Hertha Berlin's fans at the end of a tough game

Niklas Stark is a 23-year-old centre-back who currently plays for Hertha Berlin in the Bundesliga. He is also eligible to play for Germany, but the highest level he has reached so far is the U21 squad, for whom he's played 18 times.

Before he joined Hertha Berlin for £3m in the summer of 2015, Stark was trained and developed by FC Nurnberg. He featured in their youth academy, before going on to play for their U17s and U19s. Eventually, once he made his debut with the senior side, he was used frequently and became an asset.

Stark is strong and comfortable on the ball. Some would say that he's a leader who can rally up those around him, as well as lift their spirits if the side concedes. He would be an ideal player for Dortmund to have in the heart of their defence next season.

However, his price tag has risen considerably in recent seasons, and he's now valued at around £20m. Dortmund would be lucky to get him for that, though, as he's probably going to cost about £25m to persuade Hertha to let him leave.