What to expect from Borussia Dortmund during the summer transfer window?

The centre-back conundrum

Mats Hummels has performed at an incredibly high level this season, which is enough evidence to offer him a new deal in an urgent manner. At 35 years old, the veteran is playing some of the best football of his career, becoming a pivotal piece BVB's run to the Champions League final.

The final decision rests in Hummels' hands, and whatever he decides will likely play a big role in BVB's plans for the centre-back position. If Hummels stays for another season, the club could look to invest in a centre-back for the future.

Last summer, Borussia Dortmund came close to signing Armel Bella-Kotchap as a future heir for Hummels, but the deal collapsed in the final days of the transfer window.

The squad's depth in centre-backs for next season also poses a potential problem, with Niklas Süle's future is still unknown. Reports have claimed that Süle's future at the club could be in doubt after he lost his spot in the team this season, which would require BVB to sign another centre-back.

In that scenario, it would be even more vital to extend Hummels' contract and, if the opportunity presents itself, to sign a young and future successor as a backup. Tosin Adarabioyo, who is running out of contract at Fulham, could be a cheap and interesting option.