With the January transfer window finally picking up as the early pace-setters look to reinforce and those lagging behind attempt to inject some impetus into their ailing campaigns, there will doubtlessly be plenty of eyes on Jürgen Klopp’s Borussia Dortmund side.

Dortmund, last season’s Champions League’s losing finalists and Bundesliga runners up, have for some seasons occupied an unique position amongst Europe’s elite. Despite their success – they won back-to-back league titles in 2011 and 2012 – they have frequently found their status in the transfer market more befitting of a lower-half side, frequently forced to see their top players depart on free transfers or for minimal fees as their contracts run down with no prospect of a renewal.

The latest departee is a particularly galling one for Klopp and co. Robert Lewandowski, the Polish striker whose exploits include scoring four goals in the first leg of last year’s Champions League semi-final against Real Madrid, was plucked from relative obscurity and has grown into one of Europe’s most feared marksmen in the shadow of the Westfalenstadion. His move to main title rivals Bayern Munich is not just a major blow in the sense that Dortmund will see no return on their investment, but also because he’s not the first to head in that direction. Last summer saw home-grown German international Mario Götze make the switch to Munich too.

This combination of Dortmund’s ability to spot and develop world-class talent and their inability to pay them top-tier wages will have other clubs rubbing their hands together with glee, and the current Dortmund team, despite currently sitting in 4th in the Bundesliga, has no shortage of talent. However, managers looking to pluck their missing piece of the puzzle from the Ruhr Valley should bear in mind how other former Borussia recruits have fared.

Having become the most costly German footballer in history, Götze hasn’t exactly hit the ground running at the all-conquering Bayern. Restricted to just 11 league starts through a combination of injuries and fierce competition in arguably the strongest midfield in world football today, few Bayern fans will be complaining given their team’s rampant league form, but he hasn’t quite sparked as his transfer fee suggested he might.

That being said, Götze is arguably the biggest success story out of Dortmund’s major departures. The two other biggest transfers out of the club in recent years, Shinji Kagawa (now of Manchester United) and Nuri Sahin (currently back at the club on loan from Real Madrid) have both failed to live up to anywhere near the levels of hype granted them.

Kagawa’s role in the Man Utd system has been one of the most closely scrutinised aspects of David Moyes’ first season in charge, with many believing that his utilisation holds the key to the team’s revitalisation. However, on the occasions he has been used, he’s blown hot and cold, falling flat as often he threatens to recreate the kind of form that made Klopp “cry for twenty minutes” when Kagawa agreed to switch to Old Trafford. With the arrival of the positionally-similar Juan Mata, it appears that Kagawa’s cameo at the club could be drawing to a close.

However Kagawa’s shortcomings pale in comparison to those of Sahin, the deep lying playmaker who left for Real the season before. Having spent the majority of the season injured, the ten appearances he accrued at the tail end of the campaign remain his only contribution to Los Blancos. A season-long loan to Liverpool seemed well suited to his rehabilitation thanks to the tactical similarities between Klopp and Reds manager Brendan Rodgers, but that was cut short after six months with Sahin never finding his feet. The unusually long deal struck between Real and Dortmund (a loan of 18 months) is seemingly indicative that wherever Sahin’s future lies – even reunited with Klopp, his talent appears diminished – it won’t be at the Bernabeu.

Of course, these are three examples that could well prove to be exceptions to the rule. Sahin’s loss of form can be attributed to his injuries, Götze has looked promising when he’s made it onto the pitch, and Kagawa could well rediscover his edge should he bid farewell to Moyes and Man Utd. But should Lewandowski fail to ignite at a Munich, the question will remain; do the player’s make Dortmund, or does Dortmund make the players