The statement from the Borussia Mönchengladbach supporters' club was only 15 words long: "Whoever sees a derby as an ideal time for experiments has not understood Borussia Mönchengladbach."

Marco Rose had made seven changes ahead of the recent Rhineland Derby against Cologne – and it backfired, as the struggling Billy Goats won 2-1.

Ahead of kick-off, sporting director Max Eberl had been asked about Rose's future. "I'm fighting for him," he replied. Nine days later, the club announced that Rose would be joining Borussia Dortmund at the end of the season.

The worst kept secret in German football was out, months of speculation were at an end, and the Bundesliga food chain is as intact as ever. Bayern Munich's poaching of their rivals' best players – such as RB Leipzig's Dayot Upamecano – is often a cause of consternation for rival fans, but so is Dortmund's cherry-picking of talent from the rung beneath them.

"Just because Dortmund can throw money around, another tender shoot of success for our Borussia is being ripped up again," wrote the supporters' club, explaining their derby anger and predicting Rose's departure.

Yet both the fans' frustration and Dortmund's interest are rooted in the same cause: the fact that the 44-year-old has done an extremely good job in his 18 months at Borussia Park, and everybody has seen it.

The current dip in form aside, Gladbach have been a joy to watch under Rose. Home wins against Bayern Munich (twice) and Borussia Dortmund are obvious highlights, but a 2-2 draw away at RB Leipzig in February 2020 was the Foals' most accomplished display, when only a harsh red card robbed Rose of a statement victory in his hometown.

Gladbach finished fourth in the Bundesliga and qualified for the Champions League for the first time since 2016, progressing through a group which included Real Madrid and Inter Milan to set up a last-16 meeting with Manchester City. They're going toe-to-toe with Europe's elite, but the announcement of Rose's departure is a harsh reminder that Gladbach are not yet part of that elite.

Upheaval in Dortmund

Dortmund, for all their current travails, are closer and, under almost any other circumstances, would represent a logical step up. However, these are anything but normal circumstances and it's legitimate to question whether moving from Gladbach to Dortmund really does represent the next step for Rose.

Both Borussias are six points adrift of the top four and equally (un)likely to qualify for next season's Champions League, something which would represent an infinitely bigger blow to Dortmund than it would to Gladbach, in this year of all years.

BVB have spent Champions League money on a Champions League squad which is designed to compete in the Champions League every season. They have also been hit harder than most by the pandemic and lose €4 million for every home game played behind closed doors at Germany's largest stadium.

Missing out on the Champions League for the first time since 2015 would be disastrous and would make player sales inevitable. Jadon Sancho would be first out the door, but not for anywhere near the €120 million demanded from Manchester United last year. Erling Haaland played under Rose at Red Bull Salzburg, but would the Norwegian settle for the Europa League, or even less?

Beyond them, this current Dortmund team, which came close to winning the Bundesliga in the last two years but not close enough, is reaching the end of its cycle.

Mats Hummels' contract is up next year, and the stability and experience which Axel Witsel, Thomas Delaney and Emre Can were supposed to bring to midfield haven't borne fruit. Julian Brandt remains a luxury, Gio Reyna and Youssoufa Moukoko are still young, and there are even doubts over captain Marco Reus.

Upstairs, CEO Hans-Joachim Watzke and sporting director Michael Zorc have signalled that their time is coming to an end, but whether former captain Sebastian Kehl, currently head of professional football, is ready to take on greater responsibility remains to be seen.

Stability in Gladbach

This is the situation which Marco Rose will encounter at the Westfalenstadion, leaving behind him a club in Borussia Mönchengladbach which is operating on a lower plane with lower expectations but arguably, at least for the time being, with greater opportunities.

Under Eberl and financial director Stephan Schippers, Gladbach are one of the most upwardly mobile clubs in Europe, spending shrewdly in the transfer market and investing wisely in the club's academy and scouting infrastructure. Thanks to this season's Champions League revenue, Gladbach are as well placed as they can be to face the financial devastation of the pandemic.

"Our path is about continuity in key positions," Schippers told the Rheinische Post in December, welcoming Eberl's contract extension until 2026. "We want a strategy which isn't dependent on the coach, but with which our coaches can work."

Eberl has already shown what that strategy looks like in real life. In April 2019, he announced early that Rose would replace Dieter Hecking at the end of that season, and he's acted decisively again now, giving Gladbach time to identity a successor.

But his disappointment was tangible reading between the sober lines of Gladbach's statement on Monday. "We've had many discussions about Marco's future in recent weeks," he said. "Unfortunately, he has decided to make use of a clause in his contract ..."

Even the fans would have forgiven Rose for the derby against Cologne. "Marco, we would have built you a statue at the end of your time with us," wrote the supporters' club once the derby emotions had cooled. "The values, the passion and the will to win which you transmit to our team strike a chord with us and make us dream."

Given the circumstances, one wonders whether Marco Rose had to leave Borussia Mönchengladbach just yet.