By Matthew Cooper Manchester United have suffered a major blow ahead of their FA Cup quarter-final clash against Liverpool, with Casemiro missing the match after picking up another injury. The 32-year-old only returned to action in January after a spell on the sidelines with injury, but has now suffered a setback. It was revealed ahead of the game that Casemiro had been forced to pull out of the Brazil squad through injury, with manager Dorival Junior stating that Porto forward Pep had been called up as a replacement. “We have just received a report from Dr. Rodrigo Lasmar,” he said. “From a p…