One West Ham United player’s woeful performance against Manchester City today highlighted one big transfer mistake by Julen Lopetegui in the summer window. Manchester City were in imperious form today, and whilst West Ham showed exciting signs of what Julen Lopetegui is trying to implement, too many of our players had off days. The Premier League is unforgiving, and if you’re not at it, you will be shown up. Lopetegui enjoyed a fabulous transfer window, and brought in numerous top-class players who will undoubtedly improve us over time. Whilst the Spaniard hit the jackpot with most of his summ…