Transition from college to NFL is huge. Everything moves twice as fast and everyone is twice as big. Allen hasn't played football since 2016. It is going to take time to get him up to NFL speeds and intensity. He is probably also hitting the weight room hard to get his upper body ready for the hits he is going to take of the line. But these are all things that will come around. What you cannot teach is flat out speed. Allen has pretty huge advantage in that department.