By Josh O’Brien Kyle Walker limped out of England’s friendly fixture against Brazil with barely 20 minutes on the clock – and it will be a concern for Manchester City boss Pep Guardiola. Before a ball had been kicked during this international break, Walker’s City team-mate Erling Haaland revealed that Guardiola gave the side a stern warning about maintaining their fitness while away with their respective national sides. The Norwegian goalscorer was rumoured to have picked up an injury himself earlier this week, but played down such speculation. “I feel good and am ready to play the match,” Haa…