From the WSJ Econ blog:
Using survey data that followed the lives of thousands of Germans from 1984 to 2006, the German Socio-Economic Panel study, Mr. Lechner found that sports-playing adults saw a boost in income of about 1,200 euros per year over 16 years when compared to their less active peers. That translates into a 5-10% rate of return on sports activities, roughly equal to the benefit of an extra year’s worth of education.
It turns out, according to Mr. Lechner’s calculations, that only about one-fifth of that increase comes as a result of better health. “Although health and other subjective variables contribute substantially to the effects of sports activity, there remains a large unobserved and unexplained component,” Mr. Lechner writes.
Some of that unexplained component could be chalked up to social networking benefits. In fact, the sports-playing men in Mr. Lechner’s study reported a significantly higher level of “social functioning” than did the less active men.
Here is the paper.
Also worth noting, Sam Zell's plan to get the state to purchase Wrigley Field is foundering.