Manchester United striker James Wilson will have an operation after suffering an anterior cruciate ligament knee injury while on loan at Derby County.
The injury was sustained during a Derby training session on Monday and Wilson was tested on the problem back at Carrington.
After surgery, the 20-year-old striker will start a rehabilitation programme.
“It’s a great disappointment for him and for the club as well,” United reserves coach Warren Joyce told the club’s official website.
“All you can do when you have setbacks is to try to be positive and look to make sure when you do return, it’s in the best shape.”
Derby boss Steve McClaren told Derby’s site: “It’s incredibly disappointing news that James has suffered an injury like this.
“Only last week, I was saying how much I was looking forward to working with him because he is an exciting young talent.”