10 Best Players Sold By Borussia Dortmund

Now plying his trade in the lower rungs of the Spanish division, Shinji Kagawa was once an elite player at Dortmund, especially during Klopp's early years as he played an instrumental role in all the domestic success between 2010 and 2012.

The Japanese international struck 21 times in 49 appearances in the Bundesliga before departing for Manchester United where he couldn't replicate his heroics, and after two unsuccessful years, returned to the Signal Iduna Park in 2014.

He was immediately slotted back in the team and impressed once again, but his importance to the side gradually waned as the old phantom of injuries reigned in and Kagawa only featured in bits and spurts under Lucien Favre.

This prompted his departure once again, and he joined Besiktas in January last year. Even though his second spell with the Borussen wasn't laden with silverware, he still made another 145 appearances and scored 31 times.