Tottenham Hotspur have suffered an enormous blow before the summer transfer window has really got going. Ange Postecoglou can be pretty happy from a transfer perspective as Tottenham Hotspur already have two signings done and dusted. Lucas Bergvall will start his Tottenham career after signing from Djurgarden whilst Timo Werner has returned on loan from RB Leipzig. That is a good start for Postecoglou but the Tottenham boss has now suffered a major blow. Assistant coach Chris Davies has decided to leave Tottenham for a move to Birmingham City, becoming their new manager on a four-year deal. Da…