Not being a soccer fan at all, my basic picture of which countries dominate the sport is the Mediterranean and its off-shoots in Latin America. But Germany has one of the best records in the World Cup. How does that fit into the big picture?
When Germany joins with the Mediterranean more than Scandinavia or Eastern Europe, it must really be a fact about Western and Southern Germany, not Northern or Eastern. Recall this original post on the great civilizational fault-line that runs through Europe, separating the hilly and mountainous regions from those of the Great European Plain.
Western and Southern Germany are Catholic like the Mediterranean, while Northern Germany is Protestant like Scandinavia, and Eastern Germany is increasingly de facto godless like the Balto-Slavic Plains. Also recall this post showing that Eastern Germany has historically been more (Balto-)Slavic than Germanic.
So let's take a look at the roster of their 2014 World Cup team. Of 17 ethnic Germans, only 2 were born in the North, and 0 in the East. (There are also 2 Poles from Silesia.) In contrast, 5 were born in the South, and 10 in the West.* This does not map onto the size of the population in each state. Rather, there is something about hailing from the Western and Southern regions -- and it's probably not the Catholic church.
Hilly and mountainous areas tend to be favored by on-the-move livestock herders more than sedentary farmers. (The farmers squat on the low-lying fertile plains, and the herders have nowhere to go but up.) This hunch is supported by the ethnic backgrounds of the German players who aren't from the general area. One is Albanian and another Turkish, both from the mountainous region of Southeastern Europe. Another is half-Tunisian and half-German (I couldn't find out where in Germany that parent is from), and Tunisia is another mountainous pastoralist region of the Mediterranean. Another is half-German (I couldn't tell where that parent is from) and half-Ghanaian. West Africa is generally less pastoralist than Eastern Africa, although there are a good deal of herders and milk-drinkers in the West as well.
Also, Scandinavia and most of Eastern Europe failed to qualify for the World Cup to begin with. Tiny little Alpine Switzerland out-performed all of Mother Russia. Nords and Slavs dominate those strongman competitions where the goal is to re-enact the daily tasks of Conan the Barbarian.
What about pastoralism selects for good soccer players? Beats me, since I haven't given the sport any thought since elementary school. It does seem like more of an endurance sport -- all that constant jogging around -- and mobile pastoralists are going to be better at that than farmers who only need to stoop over a small plot of land all day long, day-in and day-out. (Hence the absence of Chinese soccer players.) See this earlier post about pastoralism and endurance sports.
I think being constantly vigilant is another big factor -- herders need to be on alert for anything that might run off with their livestock, whether an animal predator or a human rustler. Is the soccer ball like a member of your flock that you're steering along a course, and the opposing players are rustlers trying to drive your property away from you, and you then have to be vindictive enough to chase them down and get it back, rather than cut your losses or rely on a central authority to go get it for you? Soccer as ritualized cattle raid.
If there is an influence of pastoralism, it wouldn't be the more nomadic kind. We don't see Ethiopians and Kenyans dominating soccer like they do distance running, where we see selection for being on-the-move for a long time. Nor do Central Asians rank very highly.
The type of pastoralism practiced among the soccer nations way back when was transhumance, not nomadism. They roamed around a decent amount each day, but they did have something like a "home base" for days, weeks, and sometimes months. Over the course of the year, they'd move toward more favorable areas -- mountains in summer and valleys in winter -- but it was not like the constant meandering around with no particular destination in mind that the nomadic pastoralists practice.
There's more to look into here, but this exhausts my interest in soccer.
* Here is the list of the player's birth state and name. The non-Germans and half-Germans are listed below.
Boateng - Berlin, Ghanaian / German
Mustafi - Hesse, Albanian
Khedira - B-W, Tunisian / German
Klose - Polish
Ozil - NR-W, Turkish
Podolski - Polish