Borussa Dortmund manager Jürgen Klopp consoles striker Marco Reus after the club lost the Champions League final to Bayern Munich on Saturday in London. Getty Images

In some sports you expect coaches to overshadow players: College basketball and football come to mind. But soccer, like most professional sports, is star-driven. Coaches are ordinarily auxiliary to the narrative. They're the wacky neighbor recurring on a sitcom. They're M to James Bond.

Not so with Jürgen Klopp, a man whose disarming enthusiasm and outsize personality play as big a role as his undoubted tactical sense in explaining why he seems to embody Borussia Dortmund BVB.XE -2.45% Borussia Dortmund GmbH & Co. KGaA Germany: Xetra 4.86 -0.12 -2.45% July 10, 2014 5:35 pm Volume (Delayed 15m) : 224,303 P/E Ratio 7.03 Market Cap €306.02 Million Dividend Yield 2.06% Rev. per Employee €594,787 05/26/14 Ancelotti Still So Hard to Ass... 04/22/14 David Moyes Out as Manchester ... More quote details and news » more than any single player. On Saturday night, after seeing his team get beaten by Bayern Munich 2-1 in the Champions League final, he served up more of the same.

"The only thing I can say is it was great," Dortmund's manager said. "We really deserved to be in the final. Our fans—what they did was great. The whole atmosphere was great. We're in London, the town of the Olympic Games, that was great, the weather was great, everything was great. Only the result is so..." he added before using a word more common in the locker room than the press room.

Statements like those help explain why so many neutrals find him so endearing. But mixed in with his avuncular jocularity you'll often find a little dig.

When asked what was next for him and Dortmund, he replied, "Now I guess we'll go on holiday but then we need to go out and get some new players because seemingly everyone wants to buy our players so we'll need to replace them."

The reference was twofold and plain as day. And it underscores just why Borussia Dortmund—despite a three-year cycle that saw it win two German Bundesliga titles and a German Cup, despite reaching the Champions League final, despite boasting the highest average attendances in Europe—may struggle to build on its recent success. Simply put, despite all of the above, it's difficult for it to hang on to its best players.

Last month, it emerged that Dortmund's homegrown wunderkind, Mario Götze, would be leaving in the summer to join none other than archrival Bayern Munich. Götze had been at Dortmund since the age of 8 and had worked his way up through the club's youth ranks. In the spring of 2012, he signed a long-term contract, albeit one that included a "release clause," a fixed price for which the club would have to sell him. Bayern, of all clubs, triggered it with a $48 million fee that, as of July 1, will not just weaken Dortmund, but strengthen the archrival. We were spared the potential conflict of interest in the final as Götze missed out due to a timely hamstring injury, but the hurt of the Dortmund fans was evident. The week his imminent departure was revealed they greeted him with a banner that read: "Striving for money shows how much heart one really has. [Shove] off Goetze!"

The club's leading goal scorer, Robert Lewandowski, who notched 65 goals over the past two seasons in all competitions, is also the subject of endless transfer speculation. He is a year away from free agency, which gives him enormous leverage and puts the club in a horrid negotiating position. Do you turn down all offers and risk losing him for nothing next summer? Or do you sell him now, for what will likely be a cut-price fee?

In most U.S. sports—because of free agency, salary caps and the draft—maintaining success is extremely difficult and you come to accept that successful teams get broken up: Just look at what is happening to the Super Bowl champion Baltimore Ravens. In soccer though, the economics are such that there is a very obvious class system, with a half dozen European superclubs in a perennially dominant position where they can cherry-pick talent from their closest rivals.

Germany is an extreme example of this, because of Bayern Munich's hegemony. It's not as if Borussia Dortmund is a small club. Not only does it boast huge crowds, but it's the second biggest German club by revenue (albeit far behind Bayern). In many ways, Dortmund had done everything right in painstakingly building this team.

With the exception of forward Marco Reus, not one of the starters Sunday night cost more than $7 million. Four of the starting 11—plus Götze—cost nothing, either because they were homegrown or because they arrived via free agency. And even the $23 million acquisition of Reus was largely financed by the sale of Shinji Kagawa to Manchester United for $20.7 million last summer. Dortmund had acquired Kagawa for just $550,000 in 2010, a sterling example of the club's "buy low, sell high" virtuous cycle.

Credit for this must go to Klopp and general manager Michael Zorc, who oversees the club's scouting and acquisitions.

But it's fair to ask how many more miracles the pair can conjure up in the transfer market. And if it isn't somewhat cruel that, compared with a Bayern or a Real Madrid or a Manchester United, clubs like Dortmund—despite their history, fan base and what amounts to "best practice"—need to work so much harder just to keep up.

"We'll be fine, don't worry. We'll have a good team next year too," Klopp said, in his own way on Saturday night.

He may well be right. But you wonder how much longer clubs like his can continue to tread water as the gap between soccer's über-rich and merely quite rich continues to widen.
