Both of those sites are currently recruiting new writers - they've recruited a lot of good writers and are a great breeding pool for sabermetric talent. (I can see how Studes got confused into bringing me onboard here.)
If you're interested in being a sabermetric writer but didn't know where to start, well, now you know. And knowing is half the battled. (Go, Joe!)
Colin Wyers knows exactly how much of a nerd he is. He is very interested in hearing about any other concerns you may have; you can reach him by e-mail, and he will try his best to respond in a timely fashion. He also blogs at Statistically Speaking.
