Spitballing: Playing With Playing Time

Projecting playing time is hard. When news hit that Adam Wainwright was almost certainly out for the year, forecasters went into fits. There’s no way to predict Tommy John surgery* for a pitcher coming off back-to-back 230-inning seasons. So you can say there’s a 5% chance he gets hurt and dismiss that possibility as too unlikely to weigh into your projection, or you can drag your forecast down by 5%. Regardless of which course of action is better, the only recourse after the fact is to “cheat” by manually updating the number of projected innings when such news comes out.

Baseball Prospectus