Thomas Tuchel will not have had enough time with his Bayern Munich players to have a significant impact on Saturday's Klassiker, according to Borussia Dortmund sporting director Sebastian Kehl.

Former BVB boss Tuchel has been appointed Bayern coach, replacing Julian Nagelsmann ahead of a huge game against their title rivals.

Ten-in-a-row champions Bayern are a point behind Bundesliga leaders Dortmund heading into their meeting, hoping Tuchel can inspire an upturn in form after a run of only five victories in 10 matches let their opponents back into the title race.

But Tuchel was appointed in the middle of the international break, meaning Kehl cannot see how he would have a big say in proceedings right away.

"I don't know if FC Bayern will be better on Saturday with Thomas Tuchel than before under Julian Nagelsmann," Kehl told reporters.

"I don't think that this coaching staff will necessarily affect this game, because many international players are still away until the middle of the week and a great number of training sessions cannot take place.

"They will not have that many opportunities to work on tactical things."

Tuchel left Dortmund in 2017 after clashing with the club's hierarchy, but Kehl again does not foresee those events playing a part.

"It doesn't matter at all," he said. "I think the issues from back then have long since been forgotten and cleared up."

Kehl added: "I don't think it's a game against Thomas Tuchel at the weekend; in the end, it's between the first-placed team and the second-placed team.

"All parties are so professional. It's part of the process that coaches change and sometimes come to play against old clubs."

Either way, Kehl does not see Saturday's result deciding the title race, even if Dortmund have a huge opportunity to move four points clear.

"We can make a big step up the table because we're playing against a direct competitor," he said. "First plays second, a game everyone can look forward to.

"It's nice that we were able to make it such an exciting game. But the title will not be decided at the weekend."

Sebastien Haller says being back on the field and scoring goals for Borussia Dortmund "is all a bonus" following his recovery from cancer.

The Ivory Coast international scored twice in Saturday's 6-1 win over Koln to help Dortmund leapfrog Bayern Munich, who travel to Bayer Leverkusen on Sunday.

Despite playing football at elite level just three months after undergoing surgery for testicular cancer, Haller has come in for criticism for his lack of goals.

Prior to his brace against Koln, the 28-year-old had scored just once in 12 appearances, but he is glad to now be playing his part.

"I'm happy to be here and playing at all. It's all a bonus to me," Haller, who joined Dortmund from Ajax in July, told Sport1.

"If you think after just a few weeks everything that happened in the six months before is forgotten, that would be a big mistake."

Even without scoring, Haller still played an important role for Dortmund in terms of his build-up play, with his return to the side coinciding with a 10-game winning streak.

Dortmund's sporting director Sebastian Kehl said: "These goals will give him a boost. 

"What has been surfacing in the last few weeks is not justified after everything the boy has been through. His work has paid off and he feels the support of the whole club."

Marco Reus also scored twice in Dortmund's win against Koln to overtake Michael Zorc as the club's outright all-time record scorer in the professional era with 161 goals.

Long-serving midfielder Reus has spent 11 seasons in Dortmund's first team and reiterated he intends to see out his career at the Westfalenstadion.

"I have said it in the past weeks, months, years that I would like to end my career here," said Reus, whose current contract is due to expire at the end of the season. 

"I feel really good. We are in talks [over a new deal]. Everything else will become clear in the coming weeks."

Youssoufa Moukoko will miss both legs of Borussia Dortmund's Champions League tie against Chelsea after he was ruled out for around six weeks with an ankle injury.

The 18-year-old was replaced by Sebastien Haller in the first half of in-form Dortmund's 2-0 Bundesliga win at Werder Bremen on Saturday.

Moukoko on Monday discovered he suffered a torn syndesmosis ligament and is expected to be sidelined until late next month.

Dortmund sporting director Sebastian Kehl said: "This is tough news for him and for us, especially in the current stretch. We kept our hopes up, but unfortunately he will be out some time."

The teenager will miss the first leg of Dortmund's round of 16 clash with Chelsea on Wednesday and the return fixture at Stamford Bridge on March 7.

A showdown with RB Leipzig is among the Bundesliga matches the Germany international will sit out.

Dortmund boss Edin Terzic will hope Moukoko will be available when his side travel to face leaders Bayern Munich on March 31, with a home game against second-placed Union Berlin to come a week later.

Terzic's men are three points behind Bayern in third place and have won six consecutive games since the season resumed.

Borussia Dortmund have told Youssoufa Moukoko to finalise his future plans "this week" with the Bundesliga club wanting the draw a line under contract negotiations.

The 18-year-old striker's deal expires at the end of the season and Dortmund say they have presented him with a "very attractive offer" to renew.

According to sporting director Sebastian Kehl, the club have now issued Moukoko and his advisor with an ultimatum so the player can "devote himself entirely to the sporting challenges" before the Bundesliga resumes this weekend.

Speaking to Kicker Magazine, Kehl said: "We have put together a very attractive offer that gives him a lot of room for development. That should lead to a decision. He has to make it with his environment and his advisor.

"Youssoufa can now accept this offer and commit to Borussia Dortmund, or we will go our separate ways. I would like him to choose us because he is not yet at the end of his development and I see huge potential in him. But there are limits for us as a club. And we have shown these limits. Now it's up to him to decide.

“Youssoufa and his advisors know that we are expecting a decision this week because we want to have this clarified before the first game back [after the World Cup break] so that the boy can devote himself entirely to the sporting challenges."

Moukoko – who was part of the Germany squad at the World Cup in Qatar – became the Bundesliga's youngest ever player when he replaced Erling Haaland just a day after his 16th birthday in the 5-2 win against Hertha Berlin in November 2020.

He has scored six goals in 14 games (eight starts) in the Bundesliga this season, but Kehl believes there is plenty more to come from him.

"Youssoufa is a great boy," he said. "He's been with us for almost seven years, we trained and developed him. He became a professional and a national player with us. He received an incredible amount of support from us and worked hard to achieve success himself." 

Kehl also said Dortmund are "very relaxed" about Marco Reus and Mats Hummels, who are both also out of contract at the end of the campaign.

"From the conversations with both of them I can say that we are very relaxed about the situation," he added. "Both have already made public statements about this in the past few weeks. Mats has decided that he wants to wait and see how things develop for him. He said that publicly himself.

"Of course the players are concerned about their future. That's normal. I'm convinced that we'll find a way to progress together in talks."

Borussia Dortmund sporting director Sebastian Kehl described reports of poor behaviour from Giovanni Reyna during the United States' World Cup campaign as "incomprehensible."

Gregg Berhalter's young USA side suffered a last-16 exit against the Netherlands after finishing second in Group B at the tournament, with Reyna playing a limited role.

The attacking midfielder featured for a total of just 51 minutes in Qatar, and reports have since suggested the USA almost sent him home due to a lack of commitment in training.

Reyna labelled such reports "highly fictionalised" in a social media post on Monday, expressing disappointment that any dispute with Berhalter or his staff had been made public.

The 20-year-old has the backing of his club, with former BVB midfielder Kehl saying any questions over his professionalism are unjust.  

"The contents of the reporting on Gio Reyna have surprised us a lot in the last few days," Kehl told DPA.

"He's had a really difficult time with multiple injuries. We've known the boy for many years, even though he's only 20. 

"We see him as a good guy who works professionally and is a valued team-mate in the dressing room. 

"After a few days in Qatar, that this is now being fundamentally questioned is incomprehensible for us at BVB and does not do justice to Gio Reyna."

Having missed most of the 2021-22 campaign through injury, Reyna has also struggled for fitness this term, managing three Bundesliga starts and playing just 363 minutes in the competition.

Edin Terzic and Sebastian Kehl are "100 per cent" the men to lead Borussia Dortmund, according to the club's CEO Hans-Joachim Watzke.

Terzic replaced Marco Rose as head coach in May while former Dortmund midfielder Kehl took over from long-term sporting director Michael Zorc at the end of the 2021-22 season.

Dortmund began the 2022-23 campaign steadily, winning four of their first five games in the Bundesliga, and they qualified from their Champions League group to reach the last 16.

However, an inconsistent run in the league ended with back-to-back defeats to Wolfsburg and Borussia Monchengladbach just before domestic football halted for the World Cup in Qatar, and Dortmund found themselves in sixth place after 15 games, nine points behind leaders Bayern Munich.

“The World Cup break should have come a week earlier, after the Bochum game [3-0 home win prior to the Wolfsburg loss]," Watzke told members at the club's general meeting on Sunday. "Then we would all be in a better mood.

"That's why I can't spare the team the reproach. The two games, especially the one in Gladbach [a 4-2 defeat], weren't what we expect from Borussia Dortmund.

"But we made the decision to change with full awareness. In the team. In the position of sports director with Sebastian Kehl, after 24 years with Michael Zorc, and in the position of coach with Edin Terzic. That is the way of Borussia Dortmund. 

"Both are excellent professionals, and what is particularly important to me – and I am sure to you as well – is that you work with full passion for BVB.

"We are 100 per cent convinced of this solution, and we will be successful with it. Because both of them are great – and real Borussians. We need people who have dedicated themselves wholeheartedly to the club."

Due to the World Cup – which kicked off on Sunday – Dortmund do not play another competitive game until January 22, at home to Augsburg, giving plenty of time for Terzic to work with his players, even the ones at the tournament once they return such as Jude Bellingham and Giovanni Reyna.

With Bellingham in particular likely to be courted by most of Europe's big clubs at the end of the season, if not sooner, qualifying for next year's Champions League would give the club a stronger hand in negotiations, and Watzke is confident they will.

"I am 100 per cent convinced that we will qualify for the Champions League again at the end of this season," he added. "And anyone who knows me knows that I am not the greatest optimist."

Borussia Dortmund sporting director Sebastian Kehl allayed fears Marco Reus could miss the World Cup after the forward sustained an ankle injury against Schalke.

Reus' struggles with injuries are well-documented, and it appeared he had suffered another devastating blow when he came off the field on a stretcher in the first half of Saturday's Revierderby.

The initial outlook for Reus, who was in tears as he left the pitch, was not positive, with Dortmund head coach Edin Terzic telling Sky Sport after the game: "It looks as if the ligaments were injured. Of course, he was very disappointed and was in a lot of pain."

Reus was absent from Germany's victorious 2014 World Cup campaign with another ankle injury, but Kehl is confident he will be fit for the upcoming edition in Qatar.

"It was a shock for us, too, but I can give a little 'all clear'," he told SPORT1. "The examinations showed no fracture, just a lateral ligament injury at the ankle.

"[It is] not so difficult that the World Cup is in danger."

Reus was making his 250th Bundesliga appearance for Dortmund on Saturday, and BVB earned a 1-0 win over their bitter rivals in his absence.

Youssoufa Moukoko's winner – making him the youngest Revierderby goalscorer at 17 years old – gave Dortmund four wins in a row in this fixture for the first time since a run of eight between 1964 and 1967.

Sebastien Haller will undergo chemotherapy treatment after his testicular tumour was revealed to be malignant.

The forward, who joined Borussia Dortmund from Ajax this close-season, was diagnosed with a tumour earlier this month after complaining of feeling unwell at BVB's training camp in Austria.

Haller last week underwent surgery in the first stage of his treatment.

Dortmund sporting director Sebastian Kehl had confirmed Haller would be missing "for a few months" but added further treatment plans were still being discussed.

And a Dortmund statement on Saturday confirmed Haller's diagnosis and the need for chemotherapy.

The statement, which updated that Haller would be absent for "several months", said: "We ask for the understanding of the media and fans that, beyond the information mentioned, we will not disclose any medical details regarding the treatment of Sebastien Haller today or during the coming months."

Kehl added: "Sebastien will now receive the best possible treatment. The chances of recovery are very good. We wish him and his family a lot of strength and optimism and are with him with our thoughts at this difficult time."

Sebastien Haller is expected to be out of action for "a few months" after undergoing the first stage of treatment for a testicular tumour, Borussia Dortmund sporting director Sebastian Kehl has announced.

The 28-year-old striker left Dortmund's pre-season training camp in Austria last week after complaining of feeling unwell, with subsequent tests discovering the tumour.

Haller, who joined the German club from Ajax earlier this month in a club-record deal reported to be worth €36million, confirmed on social media that the first stage of his treatment had been successful.

Providing another update on Wednesday, Dortmund chief Kehl said further treatment plans are still being discussed and no exact return date had yet been fixed for the Ivory Coast international.

"Sebastien was operated on last week. We asked for patience at the time," Kehl said at a news conference. "The therapy is currently being discussed. There are various options.

"Sebastien will be out for a few months, but once we can be more precise about that we will communicate it."

Haller excelled in the Netherlands with Ajax during a prolific 18-month spell that included 11 goals in just eight Champions League appearances in the 2021-22 season.

That included a four-goal haul in Ajax's first group-stage match against Sporting CP, as well as goals in both of their fixtures against Dortmund.

All in all, he scored in all but one of Ajax's Champions League matches – the exception being a 1-0 defeat to Besiktas in the second leg of the last 16.

Haller's layoff is a major blow to Dortmund's hopes of challenging 10-in-a-row champions Bayern Munich for the Bundesliga title this term, but they have been tipped to bring in another striker before the season begins.

"We are working on options and ideas, but there is nothing specific at the moment," Kehl said. "He will be out for two months and we have a tough schedule until November, but our squad offers options."

Borussia Dortmund remain "relaxed" over the contract situations of Marco Reus and Mats Hummels, according to sporting director Sebastian Kehl.

Reus and Hummels have both become Dortmund greats after long periods of service, but have just one year remaining on their contracts with the Bundesliga giants.

Since Hummels joined Dortmund – initially on loan – in January 2008, no player has matched his tally of 312 Bundesliga appearances for the club, despite the defender departing for a spell at Bayern Munich between 2016 and 2019.

Reus, meanwhile, is fourth on that list with 243 league appearances, and his 108 Bundesliga goals are the most by any player in that time for BVB.

Both players were part of the squad that reached the 2012-13 Champions League final, a side that also featured current sporting director Kehl. 

Speaking to Sky Sports, Kehl expressed confidence both Germany internationals would pen new deals, saying: "We are relatively relaxed about it. We have a very, very high level of trust. 

"We know that a few contracts will expire next year. And Marco and Mats are very, very important for this club. 

"They have helped shape this club in recent years, they stand for this club and bring an incredibly high level of identification with them: Marco as our captain and Mats as second captain.

"We will discuss this together in due course. We approach it very calmly, we have an incredibly high regard for these two players. 

"I believe that they can also be very relaxed in this situation. Because in the end we all want to be successful. For that we need good performances, for that we need Mats and Marco."

But speaking to Ruhr Nachrichten on Wednesday, Hummels, who started 20 Bundesliga matches during an injury-affected 2021-22 campaign, expressed his belief he must earn any new deal with the club.

"I want to help the team and not just be a weight," the defender said. "I even recently said to sporting director Sebastian Kehl that I wouldn't be renewing with me at the moment."

Dortmund have reinforced their defence with the signings of Nico Schlotterbeck and Niklas Sule.

Borussia Dortmund are "on the right track" to secure the prized signing of Salzburg striker Karim Adeyemi, according to Sebastian Kehl.

Kehl, who will move from a player licensing role at Dortmund to become sporting director next season, expressed optimism that the Bundesliga giants will acquire a talent who has also been linked to Manchester United.

It may be that Adeyemi directly replaces Erling Haaland, who looks set to leave Dortmund after two and a half highly successful years with the club.

Haaland is another Salzburg old boy who has flourished in the German Bundesliga since leaving behind its Austrian equivalent, with Manchester City emerging as favourites to sign up the Norway striker in a big-money deal.

Adeyemi is 20 years old and already a full Germany international with three caps and a three-time Austrian Bundesliga winner, so his signing would be a coup for Dortmund.

Kehl told Sky Sport: "The gut feeling got better over the week. We're on the right track."

Recent reports in England have claimed United made a move for Adeyemi but were rebuffed by the player, who was said to prefer a return to his homeland rather than a Premier League switch.

A technically gifted and rapid forward, Adeyemi has long been considered one of Germany's most promising young players, having cost Salzburg a reported €3million when he was 16 and joined from Unterhaching. Adeyemi had left Bayern Munich's youth ranks six years earlier.

This season, he is the leading scorer in Austria's top flight, with 17 goals in 26 games, while he also netted three times and had one assist in eight Champions League games – a European campaign that ended with a last-16 defeat to Bayern.

While Haaland's departure would undoubtedly harm Dortmund, the potential arrival of Adeyemi continues what looks to be a strong transfer window for BVB, who have already reached agreements with centre-backs Niklas Sule and Nico Schlotterbeck.