Lefty/Righty Splits (Pitchers)

Much like my hitters post, I will be going through the Braves’ pitchers and their platoon splits.  Like the hitters, the same statistics will indicate strength of a split on a particular side: LD%, GB%, BB%, and K%.  Unlike hitters, pitchers have additional control of their platoon splits with their repertoire.  In general, pitches can be grouped into three categories: same-side effective, opposite-side effective, and neutral.  These categories mean effective in the pitcher’s perspective.  As a general rule of thumb, pitches hard and in or soft and away are the toughest to hit.

Same-side effective:  two-seamers, sliders
Oppo-side effective:  cutters, changeups
Neutral effectiveness:  four-seamers, curveballs

In 2011, Hudson walked more hitters, allowed more line drives and less groundballs against lefties.  This is expected of a right-handed sinkerballer.  Lowe struck out a lot more righties, but his batted ball profile was much better against lefties.  A lot of that was due to the increased usage of his changeup.  Jurrjens, despite having a fairly neutral repertoire, had enormous BB and K splits, having a much better ratio against righties.  Hanson and Beachy each only saw changes in their batted ball profile, allowing a lot more line drives and less groundballs against lefties.  Minor had a much better K/BB ratio, despite his best pitch being his changeup.

Kimbrel’s only big difference was a much lower LD% allowed versus lefties.  Venters is pictured above due to his enormous splits.  He walked nearly half as many lefties, while striking out nearly twice as many such hitters.  O’Flaherty walked nearly no lefties, while striking out a few more.  He also limited line drives against lefties, turning those batted balls into groundballs.  Martinez struck out more righties and allowed less line drives against them.

These one year totals are not necessarily indicative of projected rates or career normals.  They are still fairly small sample sizes, especially for relievers.  Also, pitchers do not face the same talent level from each side of the plate.  For example, Minor likely only sees the better lefties and will face mediocre righties who are normally not in the lineup.  All of these statements are tendencies more than rules, since variability still plays a great part in results.  I hope this series helps in evaluating and projecting platoon splits.