By Matthew Cooper Manchester United star Casemiro has been axed by Brazil for the upcoming Copa America, with the midfielder seemingly paying the price for a disappointing season at Old Trafford. Casemiro enjoyed an impressive first campaign after making a big money move from Real Madrid, but his performance levels have dropped this season and Brazil boss Dorival Junior has dropped him from the national team. The 32-year-old captained Brazil when they beat England 1-0 during the last international break in March, but his future is now in doubt. The likes of Douglas Luiz, Joao Gomes and Bruno G…