Tottenham reportedly interested in Denmark midfielder.
Delaney is a Denmark international teammate of Christian Eriksen and turned down an approach from Burnley in the summer.
He is under contract at Bremen until 2021 but is keen to take the 'next step' in his career.
Bremen would look for at least 15 million Euros for his signature, according to the Weser Kurier (a minimum £13.5m).
The 26-year-old is in tremendous form, recently scoring four goals in two World Cup qualifiers, including a hat-trick against Armenia.
He followed this up with a goal at the weekend in Bremen's 1-1 draw at Hertha Berlin.
Delaney is a central midfielder and so breaking into Tottenham's first team would be tough, but a role could open up for him if Spurs can find a buyer for Moussa Sissoko.