The coach of the Bundesliga champions is not expecting an easy game on Friday and stated that Werder are much stronger than last season
Werder Bremen are currently second in the league, with 16 points from eight games, and trail leaders Bayern Munich by just three points.
As Dortmund prepare for what looks to be a tricky trip north, Klopp noted that the Weserstadion outfit have improved considerably when compared to last season, when they finished 13th in the league.
"Werder for me are the comeback of the year," Klopp said at a press conference. "They play an attractive game, as we all have seen in recent seasons.
"They will not sit back and give us an open game, they have always played solid football against us."
The Dortmund coach confirmed that Lucas Barrios is not yet fully fit, and his role as a starter against Bremen is in question.
"Barrios will be able to play much more than he did against Augsburg, but he is not yet ready for 90 minutes at full throttle," Klopp explained.