Manchester United invested in signing Joshua Zirkzee over the summer but there are early question marks over the Dutch striker. Rasmus Hojlund blew hot and cold in his first season at Manchester United and it became abundantly clear that another striker was needed. United had to take he pressure off Hojlund and went back to the Serie A market with a deal to sign Joshua Zirkzee from Bologna. So far, we are yet to see just why United paid £36million to sign Zirkzee with the Dutchman struggling for goals. Ruud van Nistelrooy is predicting success for Zirkzee but there are legitimate questions abo…