Manchester City defender, Kyle Walker was forced off during England’s 1-0 defeat to Brazil on Saturday, in what is an injury blow ahead of their crucial Premier League clash with Arsenal. Walker picked up what appeared to be a hamstring problem and was substituted in the first half of the friendly at Wembley. City host the Gunners at the Etihad Stadium on Sunday, with both teams separated by one point at the top of the table. “We don’t know [how serious it is]. “He’s not had many injuries so he’s not sure if it’s just tightness or something more serious. We’ll know more over the next few days,…