The Manchester City winger will be joined on the metaphorical sofa by Freiburg striker Nils Petersen, who only ever had an outside chance of making the trip; Bernd Leno, the Bayer Leverkusen goalkeeper, who fell victim to Manuel Neuer's timely recovery as Germany's No. 1 and captain; Jonathan Tah, who had only been training in Eppan as a back-up for Jerome Boateng, in manager Joachim Low's words.

But the decision to omit Sane was a lot less predictable, to put it mildly. The 22-year-old's superlative season for the Premier League champions had made him one of the most exciting prospects for this summer but Low, a pragmatist in fancy clothing, is less concerned with Sane's undeniable promise. His focus is narrower and he doesn't care much for perception or reputation.

The Bundestrainer's criteria ahead of his sixth tournament in charge are more hard-nosed: He wants players who have performed for him and who fit into his team, both tactically and socially. On all those three points, Sane has been found lacking, albeit not exclusively due to his own fault.

"Leroy is a great talent," Low said. But, he continued, he had not had made his mark in previous games for the national team. The German word he used was angekommen -- arrived -- implying that Sane had failed to connect, on and off the pitch, in a meaningful way with his teammates. There was another clue when Low mentioned that Leverkusen's Julian Brandt, the fourth wide player at whose expense Sane was dropped, had gone to the Confederations Cup.

Sane had not, by contrast, opting instead to have a surgery on his nose last summer. That decision had not gone down well with the German FA hierarchy at the time; Low and team manager Oliver Bierhoff felt that the player would have done better to use the chance to stake his claim for the World Cup squad.

The snub should not be misunderstood as a vindictive act, however. Low's main concern was to have a squad that works, in matches and between them. In Thomas Muller and Marco Reus, he name-checked his preferred starters in wide areas, with Brandt and Julian Draxler as options off the bench. Low did not feel that taking Sane as a fifth wide attacking midfielder warranted leaving a defensive player at home.

"We needed balance," Low said and it's conceivable that the Germany coach had doubts about Sane accepting the role as fourth- or fifth-choice on the flanks. The experience of Euro 2012 has taught him about the dangers of having players in the travelling party, who do not accept their position in the pecking order.

These "soft" considerations go some way to explain Sane missing out but they do not shed light on why he is not seen as crucial in the first place. One reason are the numbers: In 12 games for the senior team, he has never found the target or played convincingly. Against the deep, reactive opposition that Germany inevitably face, he has struggled to pick up dangerous spaces and pace on the left flank and often cut an isolated figure.

There's an argument that Sane gets cramped by Toni Kroos acting as a playmaker on the inside left of central midfield and that he's not adept at contributing to a controlled, slow approach (see German tactics bloggers Spielverlagerung for more on that).

But one wonders if it might not have been possible to tweak the final-third approach to utilise Sané's one-vs-one skillset. Low obviously felt that too much work was needed and thus opted for more ready-made options, who combine penetrative runs with ball domination.

Sané's explosive runs will be most missed in the latter stages of games, when he could have come on as a substitute but, then again, Low has a striker in Timo Werner, who can do a similar job from a more central position.

In the end, Low simply didn't think Sane was what Germany needed. Due to the youngster's negligible impact at international level, a genuine sense of surprise at the news is unlikely to give way to bouts of anger or more serious recrimination, should Germany's title defence fail.