If Borussia Dortmund weren't already in crisis, they are now. Tuesday night's defeat against Tottenham Hotspur in the Champions League was their fourth in their last five games in all competitions, and left the European knockout rounds beyond them. Next up is perhaps their biggest game of the season; the unforgiving Ruhr derby. 

After the loss to Spurs, Dortmund head coach Peter Bosz admitted a derby defeat to Schalke would probably cost him his job. To prevent that from happening, both the Dutchman and his team need to deliver a drastically different kind of performance to what has been on show in recent weeks. Here are five changes that might turn Bosz's fortunes and Dortmund's season around.

1. Unleash Aubameyang

Whether it was down to repeated tardiness, his bromance with French football freestyler Sean Garnier, or a combination of the two, Pierre-Emerick Aubameyang was left out of Dortmund’s trip to Stuttgart last Friday. They lost 2-1.

In fairness, the former African Player of the Year had been in woeful form – failing to score in his previous five appearances - yet he remains the side's most potent goal threat. Against Tottenham in the Champions League on Wednesday night, he spurned an early chance, shooting wide in a one-on-one with Hugo Lloris when hitting the target would have been easier. It looked as if the goal drought would continue. Soon afterwards, he scored the opener with ice-cold efficiency. It could prove to be a huge confidence boost.

Against Schalke on Saturday, 'Auba' must return to BVB’s Bundesliga lineup, where his pace is certain to unsettle the Bundesliga’s second best defense.

2. Get Bartra back on track

Borussia Dortmund are nice. In just about any other walk of life, nice is a good thing. In football, it’s essentially a byword for pushover and in recent weeks, that is what Dortmund have been. Short on aggression or players leading by example, BVB need to wrestle back control.

Sokratis is injured and Ömer Toprak is still finding his way back to fitness, which leaves Dortmund light on central defenders.

Marc Bartra needs to step up. A fine passer with a good turn of pace, Bartra has always thrived alongside a bruiser willing to take-on the dirty work. One day, this player may well be Dan-Axel Zagadou, but right now the Frenchman remains an inexperienced 18-year-old.

It’s time for Dortmund’s Catalonian nice guy to roll up his sleeves and lead from the back. If he does, others will follow.

3. Back Bürki

It’s fair to say Roman Bürki has received his fair share of criticism lately. While the shocking back-pass debacle against Stuttgart could hardly be blamed on the Swiss international, he’s not exactly been a beacon of tranquility in recent weeks.

Against Tottenham, he was back to his imperious best, pulling off a wonderful save from an Eric Dier header moments after denying Christian Eriksen from point-black range. But he was soon forced to leave the field with a head injury.

Peter Bosz will be desperately hoping that Bürki is not only able to play on Saturday, but that his first half performance against Spurs was more than an isolated purple patch. If he can't play, Roman Weidenfeller will be asked to roll back the years to ensure his absence isn’t too keenly felt.

4. Trust Weigl

A lot will depend on Julian Weigl this weekend. When in form, the deep-lying playmaker is a delightful player, bounding across the turf like a spring lamb, hoovering up stray balls and creating chances with a calmness that belies his 22 years.

Of late though, Weigl has not been in form. Returning from a long injury and then adjusting to a new tactical setup where Bosz wants him higher up the pitch, Weigl has wobbled.

The most telling evidence of an in-form Weigl is best seen in the performances of those playing ahead of him. Against Spurs, Mario Götze and Andriy Yarmolenko frequently found pockets of space where they could threaten Tottenham’s backline. Weigl is key to this, and if he can deliver a calm and assured passing performance from deep, Dortmund's play in the final third should improve noticeably.

5. Cut the talk

Captain Marcel Schmelzer delivered more words after another Dortmund defeat. The 29-year-old appears at home deflecting a crisis.

"I think that we, the players, must take responsibility," he said. "The coach chooses the lineup but we are the ones on the field. We played well in the first half, which would not have been the case if the coach didn’t have our support."

Following Dortmund’s loss to Stuttgart, Schmelzer said the team had taken a step in the right direction in terms of their attitude.

It seems Dortmund can't even talk a good game any more, let alone play one. While more words will come ahead of the derby, it's time for Dortmund to perform rather than preach.