Doubts have been cast over the 22-year-old's long-term future at Stamford Bridge after he was dropped from the first-team picture by Jose Mourinho.
The Blues boss insists the Belgian starlet remains part of his plans heading forward, but interest from afar has been sparked.
Werder Bremen would welcome the opportunity to re-sign a player who starred for them during a season-long loan in 2012/13, but they would face stiff competition from a Bundesliga rival.
Wolfsburg are closely monitoring De Bruyne's situation in England and are prepared to join the hunt for his signature if the transfer door is opened before January.
Allofs told Sky Deutschland: "We as a club have given our signal of interest in the services of Kevin De Bruyne. This was done over the summer when it became obvious that he would be returning to Chelsea.
"Kevin De Bruyne is no first team regular at this point in time. We will definitely consider what is going on with him."