The newest toy (or tool, depending on seriously you take these things) at the baseball-reference .com Play Index is a Rookie button that allows one to search for rookie seasons only. The tool will not line up perfectly with players who have been considered “rookies” historically because (1) b-ref uses the current MLB rookie definition and applies that uniformly to all seasons going back in time, and (2) b-ref is fudging a bit on the service time part of the rookie definition, so it can be applied within the scope of the data b-ref has. But the results are still very useful and interesting, and with b-ref’s prominent position in the world of historical baseball data these days, I wouldn’t be surprised if b-ref’s approach to defining a “rookie” becomes the standard definition for historical purposes.
Using b-ref’s new Play Index tool, here are (after the jump) the top rookie seasons by non-pitchers (1901-2012) for each current franchise, by season Wins Above Replacement (using the b-ref version of WAR of course): Continue reading