Senegal striker Mame Diouf has turned down an offer of an early contract extension from Hannover.
The German Bundesliga club's sports director Joerg Schmadtke told Kicker magazine that Diouf rejected a new deal that offered improved conditions.
Reports say Diouf wanted a clause that would allow him to leave at the end of the season for a set transfer fee but the club would not agree.
The 25-year-old's current deal expires at the end of next season.
He has been linked with a move to Borussia Dortmund as a possible replacement for Robert Lewandoski, should the striker leave the club at the end of the season.