Monthly Archives: December, 2014

Historic Event in the History of the Phillies

As most of you know, Jimmy Rollins was traded to the Dodgers yesterday. Rollins, or more affectionately J-Roll, was one of the key Phillies players for many years and was a big reason for their success and the World Series championship of 2008. The Phillies won’t be the same in 2015 — maybe this is the official beginning of their rebuilding.

I think the Dodgers know who they are getting in Jimmy Rollins — good defense, a smart player with good baserunning skills, and a hitter with some power. Following up my recent post, I think players can be characterized by their proportions of different batted types and J-Roll is no exception.

Using Retrosheet play-by-play data, I have collected the proportions of different batted ball types for the seasons 2000-2013 and graphed them below using the ggplot2 package.


In the early stage of J-Roll’s career, he hit a relatively high proportion of flyballs and a low proportion of line drives. But by 2005, his proportions of different types of batted balls stabilized to the values 42% (groundball), 28% (flyball) and 20% (line drive). I would expect him to display a similar set of percentages for the Dodgers in the 2015 season.