Alarm bells are ringing loud and clear at Signal Iduna Park as Borussia Dortmund external advisor Matthias Sammer has launched a stinging attack on the club’s culture. The former Ballon d'Or winner has backed Nico Schlotterbeck’s recent brutal assessment of the squad, claiming the Bundesliga giants are suffering from a debilitating 'addiction to harmony' and a distinct lack of genuine leadership.The crisis at the Westfalenstadion appears to be deepening, with internal rifts now spilling out into the public domain amid a questionable run of form that has seen them win one of their last four matches across the Bundesliga and Champions League. After defender Schlotterbeck tore into his teammates following a Champions League collapse that ended in a 2-2 draw with Bodo/Glimt, many expected the club hierarchy to close ranks and protect the squad. Instead, club legend and current external advisor Sammer has poured petrol on the fire, validating the centre-back's outburst and suggesting that the problems at the club run far deeper than a single bad result.The atmosphere in the Ruhr Valley has turned toxic in recent weeks, with head coach Niko Kovac coming under increasing pressure. The European slip up served as a breaking point for Schlotterbeck, who launched a furious tirade against the team's "extremely sloppy" performance, specifically targeting the lack of impact from the substitutes bench. Rather than reprimanding the player for airing dirty laundry, Sammer’s intervention has effectively confirmed that the defender’s frustrations are shared by those at the very top of the club's advisory board.Speaking on Sky Sport, the 1996 European champion offered a scathing psychoanalysis of the current state of the club. Known for his relentless mentality during his playing days, the advisor argued that the atmosphere at Dortmund has become too comfortable, preventing the team from reaching the elite level required to challenge for titles."The club does not lack harmony," he explained, dismantling the idea that the squad is fractured by infighting. Instead, he argued the opposite is true to a fault. "Borussia Dortmund is addicted to harmony. That is also what defines the club in its connection, in the love with the people."However, he insisted that this desire for a peaceful existence is holding them back. He stressed that if BVB wants to take "the next step," they must learn to embrace "constructive criticism" rather than shying away from uncomfortable conversations. For the former sweeper, the culture of niceties has bred a softness that is being exposed on the pitch when the pressure ramps up.Looking for smarter football bets? Get expert previews, data-driven predictions & winning insights with GOAL Tips on Telegram. Join our growing community now!The catalyst for this executive intervention was Schlotterbeck’s post-match interview, where he did not mince his words. The German international explicitly targeted the substitutes who entered the fray, accusing them of "losing every ball" and failing to match the intensity of the game. While such public dressing downs are often frowned upon by PR-conscious clubs who prefer to keep conflicts internal, Sammer leaped to the defence of the 26-year-old defender."But it was the truth," the 58-year-old stated firmly. "We have to stop blurring the truth in the end so that those who name the truth end up being the stupid ones. I thought it was wonderful what he said. He named the truth, and a leader is allowed to do that, must do that; it is his task."Add GOAL.com as a preferred source on Google to see more of our reportingPerhaps the most damning part of Sammer’s assessment was his critique of the current hierarchy. Without naming specific names, the advisor suggested that the players currently wearing the armband or holding senior status are not fit for purpose when the going gets tough."In the perception of what he does, there are people who have wonderful character traits but no leadership qualities," Sammer said, in a comment that will surely unsettle the dressing room dynamics. "Of course, they are frightened at the first moment."He continued with a blunt assessment of the situation: "But if that wasn't the problem at Borussia Dortmund and everyone saw it, then we wouldn't have the problem. It is quite simple."The fallout adds another layer of complexity to Schlotterbeck’s future. The player is clearly frustrated by the standards around him and has now been publicly backed by a club icon as the only one brave enough to speak the "truth." This creates a potential rift between him and his teammates, and pushes him towards a crossroads in his career.With his contract situation already a topic of debate and the club in a state of flux, the defender is attracting significant interest from elite clubs. It is understood that if Dortmund cannot match his ambition he could end up leaving the club as early as the summer. Premier League giants Liverpool and potentially Bayern Munich are watching the situation with keen interest. If the only "leader" Sammer identifies decides that the environment is too soft for his ambitions, Dortmund’s problems may be about to get significantly worse.