Hannover defender Per Mertesacker has failed to agree an extension to his current contract.
The German international is contracted to The Reds until June 2008 but early attempts to tie the defender to a long-term contract have broken down.
Werder Bremen have been continually linked with the 21-year-old and the news of a breakdown in talks is likely to refuel speculation.
"We couldn't come to any sort of agreement so his contract will remain as it is," Mertesacker's agent Roman Pletz told German media.
Hannover could now be tempted to sell one of their top assets if the price is right.