Over on MASN, Matt Kremnitzer provides Camden Depot's latest contribution with a piece describing the marvelous success Chris Davis has seen against left-handed pitchers. In a vacuum, this might not seem all that impressive because Davis has emerged as an elite hitting first baseman. You tend to expect elite hitters to hit well off anyone, but what is remarkable here is that his wRC+ is almost equivalent no matter the handedness of his opposition. That is interesting.
In general, all hitters fare worse against same-sided pitching. Left-handed batters tend to do worse same sided than right-handed batters. This platoon hitting is something that almost to a rule continues through a batter's entire career. To my knowledge, nothing has improved upon Dan Fox's work at Baseball Prospectus (he is now with the Pirates alongside former Camden Depoter Stuart Wallace and, friend of the Camden Depot Highball podcast, Andrew Gibson). Briefly, the age curves for same and against handed hitting are equal except against handed hitting maintains a performance advantage throughout the entire career of a player.
Of course, these are averages, which are usually to describe the population of players as opposed to individual players. Unfortunately, I must be more anecdotal instead of purely quantitative and note that I am unaware of players correcting a platoon split without them being in their teens or shortly out of their teens or if the player completely overhauls his swing.
What influences this platoon performance? What comes to mind first is that breaking balls move away from the batter, which means that they occupy the hitting range for a more brief period of time. That brevity creates the challenge, which may be further expounded by poor pitch recognition, poor batting approach, or less desirable batting mechanics. When a young player improves, it often is a result of fixing a swing or learning how to approach plate appearances. For an older player, these corrections have often already been employed without success.
It makes me wonder if the new performance (in an albeit small sample size) informs us about a new talent level for Davis or is a warning sign that he is more a 2012 Chris Davis. Read Matt's column for more nuance.