#3. Sol Campbell
Never mind Lewandowski’s move, this transfer is by far the most controversial on the list. Mario Gotze set a precedent when he switched from Dortmund to Bayern but for this departure there absolutely was not one. The rivalry was fiercer and the player was more important. Sol Campbell shocked the football world when he made the incredible move from Tottenham Hotspur to Arsenal in the summer of 2001. Campbell became an instant traitor at White Hart Lane and few players have received such a hostile response as the defender did he returned to the Lane with his new Arsenal teammates. The move worked out well for Campbell who was a part of the 2003-4 Arsenal Invincibles team.