The CEIS Football Observatory has released their 2014 FIFA World Cup preview, with a statistical breakdown at which clubs players involved with their national teams have been plying their trade during World Cup qualifying. In their breakdown of the United States we learn that by minutes played the US was the top employer of players on the national team.
The biggest minute getters were Clint Dempsey and Tim Howard, which puts England as second on that list of employers; a bit misleading. Three of the top five employers were MLS teams, with Sporting Kansas City (Graham Zusi, Matt Besler) leading the way. The LA Galaxy came in fourth, with Landon Donovan's sabbatical dropping the Galaxy USMNT pair (Gonzalez and Donovan) below Tim Howard's minute total.
Less encouraging is the numbers beyond the MLS trio of Sporting Kansas City, Seattle Sounders (Eddie Johnson, Brad Evans, later Dempsey), and LA Galaxy there isn't an MLS team in the top ten. Kyle Beckerman at RSL got 238 minutes in qualifying, but that's almost half the minutes Clarence Goodson got while playing for Brondby in Denver.
By a percentage of minutes, 26.5% of the national team played in the domestic league. While that is the highest percentage of any of league for the USMNT, 47.6% played in a Big 5 league (England, Spain, Germany, Italy, or France).
Still, the numbers show a sea change. If this same survey were done for 2014 national team appearances, Clint Dempsey and Michael Bradley joining MLS would cause a major shift in domestic minutes. Brad Guzan is the assumed heir apparent to Tim Howard age 35, and with Nick Rimando only a year younger it's unlikely that changes, but the outfield is trending more and more domestic.
As the marketing tagline goes, at least in 2014 it all starts here.