Bayern Munich and Germany legend Bastian Schweinsteiger believes that Manchester United made one major mistake and it set the Premier League club back “many years.” Bastian Schweinsteiger enjoyed an incredible playing career with Bayern Munich before he left the club in 2015 and made a surprise move to Manchester United. The 39-year-old former midfielder arrived at Old Trafford and was reunited with former United manager Louis van Gaal, who had managed him at Bayern. Schweinsteiger made 35 appearances for the Red Devils and scored twice and picked up two assists during his two seasons at Old T…