Borussia Dortmund coach Jurgen Klopp says Friday's clash with Hoffenheim is a "High Noon" showdown for the Bundesliga's bottom side to prove they can turn around their dire league form.

Dortmund are enduring the worst start to a league season in their history and last Sunday's 2-0 loss at Eintracht Frankfurt was their eighth defeat in 13 league games.

But Klopp says his side must show their mettle and has threatened to make changes against seventh-placed Hoffenheim with Dortmund having claimed only 11 from a possible 39 points.

"Friday is our High Noon. We have to show what we are made of," Klopp said in Wednesday's press conference.

"We are trying to find out in training who can withstand this situation and will make our selection accordingly."

With Dortmund already through to the Champions League's last 16, Klopp admits his side's problem comes down to attitude having lost to the likes of Hamburg, Cologne, Hanover 96 and Frankfurt, who Borussia would have comfortably beaten last season.

Klopp is hoping to have his options boosted by the possible return of Poland winger Jakub Blaszczykowski and Dortmund captain Mats Hummels from a knee and sprained ankle injury respectively.

Klopp has been given a job guarantee by Dortmund chief executive Hans-Joachim Watzke until his contract expires in 2018.

The 47-year-old, who led Dortmund to the Bundesliga title in 2011 and 2012, as well as the 2013 Champions League final, has said he is 'responsible' for getting Borussia out of trouble and has vowed not to quit.