"Whether he is ready for the first team depends on how much progress he makes. We hope it will be a quick progress, maybe two or three years," Ferguson told the Xinhua news agency.
"It takes one year to adjust to a new country and a new language, but I think Dong will adjust and progress quickly.
"The obvious one is to learn the language, especially on the training field and in the games. It is very difficult otherwise.
"Also adjusting to a new culture, you must embrace new cultures and not find fault with them or compare them. If you can absorb a new culture, then that is a huge help."We hope he will progress to become a useful centre forward and a benefit to us in the future."