The 19-year-old attacking midfielder penned a three-and-a-half-year-deal after passing a medical on Thursday.
Werder manager Klaus Allofs said: "It was a fantastic opportunity to snap up a young player who has great pace, is technically talented and possesses an amazing amount of potential."
Copyright (c) PA Sport 2008, All Rights Reserved.
Do YOU want to write for GiveMeSport? Get started today by signing-up and submitting an article HERE: https://www.givemesport.com/writeforgms