For all the sudden and unexpected success he brought to a previously crippled Borussia Dortmund, Jurgen Klopp will be forever remembered as a hero of the club. But even heroes have their weak points. And for Klopp, it seems that his reticence to use his squad's depth is a growing problem.
Dortmund have for years possessed a rather thin squad, capitalizing on a lucky run with relatively few injuries as they won the Bundesliga in 2011 and 2012. And this season, Ilkay Gundogan, Lukasz Piszczek, Marcel Schmelzer, Mats Hummels, Neven Subotic, Sven Bender, Jakub Blaszczykowski and Henrikh Mkhitaryan have all spent a month or more on the sidelines.
Yet, what little depth Klopp has had at his disposal he has rarely put to use. Jonas Hofmann, Marvin Ducksch, Julian Schieber and Milos Jojic have hardly played. Granted, all are naturally situated in attack, an area in which BVB have suffered very few injuries. But even so, a lack of rotation has left Klopp with no choice but not to trust his backups and, when needed, he has therefore chosen to trust in often-fatigued or out-of-form stars.
Consider last week's 3-0 loss to Hamburg, for example. Robert Lewandowski, who was later revealed to have suffered from the flu, played anonymously for 67 minutes. At the start of the second half, it was Marco Reus—in his first game in two weeks following a muscular injury—who was relied upon to come off the bench and deliver the spark BVB needed to overcome what at the interval was a one-goal deficit.
Lewandowski played like he was, an ill man; his substitution came with BVB 2-0 down entering the final quarter of the game. Ducksch replaced him off the bench and within minutes, the 19-year-old nearly scored with a volley and again with a header. Reus struggled, meanwhile, but Klopp only introduced Hofmann for the final quarter hour.
Klopp clearly has little faith in his bench, and perhaps that is understandable given that his substitutes have precious little experience as professional footballers. But a bench exists not only to provide fit bodies in the event that a starter is injured, it also serves the purpose of providing secondary and tertiary options. Options that Klopp has rarely opted to use.
It's a fair point to make that Dortmund have rarely blown out opponents this season; far less often than in years past. And given their third-placed standing in the Bundesliga table, they can't afford to risk dropping points in the name of keeping stars fresh and giving match practice to the up-and-comers. But when Klopp has had the chance to give his fringe players playing time in a "safe" setting, he hasn't taken advantage of his opportunities.
Consider BVB's recent wins against Frankfurt and Bremen. In both games, Dortmund were 3-0 ahead within 48 minutes. Yet against Frankfurt, Jojic, Hofmann and Schieber came on in the 68th, 71st and 81st minutes, respectively. Against Bremen, the first two substitutes were Sebastian Kehl and Kevin Grosskreutz; Hofmann was given a run out for the final 13 minutes.
Both matches, and arguably Tuesday's 4-2 Champions League win over Zenit, were ideal for not only resting the usual starters, but giving up-and-coming players a real chance: To gain experience, build confidence and earn Klopp's trust that, next time he finds himself in a difficult position (as in Hamburg last Saturday), he doesn't have to hope that unfit stars will produce the necessary moment of brilliance needed to win a match.
Dortmund's biggest squad problem now is their lack of depth, something that for the most part has been unavoidable. Nearly any team in the world would struggle to cope with the number of injuries BVB's players have sustained this season.
But unlike injuries, the readiness of Hofmann, Ducksch, Jojic and Schieber is a variable that is entirely under Klopp's control. He's had the chance to prepare them, but not taken it. And Dortmund have suffered. A rare mistake, but one that has and will continue to cost BVB dearly until it is corrected.