Carlos Lee, Aging, and Platoon Splits

One of the question marks for this year's Astros is whether Carlos Lee can rebound with offensive production similar to his career levels.  Most of you know that Lee had a down year in 2010.  At age 34, we don't know if this was mostly aberration or aging.  Since hitters sometimes show more up and down yearly performance as they age, a rebound is certainly possible. 

But an aspect of Lee's performance last year--his platoon splits--raise a question as to whether the deterioration in his offense is driven by diminished ability to hit right hand pitchers.  Here are Lee's batting splits vs. LHP and RHP in 2010, as well as the early platoon splits for 2011:



(Batting Average, Isolated Power, OPS)

2010 (vs. RHP) .238, .170, .771

2010 (vs. LHP) .274, .170, .680

2011 (vs. RHP) .185, .055, .461

2011 (vs. LHP) .538, .462, 1.538

On a career basis, Carlos Lee shows a platoon split of 11 points for batting average and 10 points for OPS.  The normally modest platoon split becomes a large gap in 2010. The 2011 batting splits are based on a tiny early season sample, and shouldn't be relied upon at this point.  However, it is at least curious that Lee's significant Right/Left splits in 2010 are followed by a continued large platoon split in 2011.

This raises a question: Do players tend to experience a larger gap in platoon splits as they age?  Since we don't have sufficient information yet to answer questions about Lee's future platoon splits, maybe I can explore this more general question.

To study the issue of aging and platoon splits, I selected 10 very good offensive players who batted throughout the previous decade.  By selecting star quality hitters, I minimize the possibility that the players were used as platoon players during their careers.  To measure offensive performance, I used wRC+ (weighted runs created plus).  The 10 players were selected based on highest wRC+ for the period, 2000-2005.  I excluded players who were born before 1972 or whom did not play during the period 2008-2010.  I divided the group into lefthand batters and righthand batters in order to measure the reduction in performance versus same arm pitchers.  Two switch hitters were considered, Lance Berkman and Chipper Jones.  Because of the strong dominance of Berkman's lefthanded batting, I included Berkman as a lefthand batter.  I excluded Jones because his dominant batting side is not unambiguously clear.

My objective is to compare the batters' offensive reduction facing same side pitchers for the periods 2000-2005 and 2008-2010.  The 2008 - 2010 period represents the aging period.  The players do not have identical ages during that period, but all of the players are well into their 30's.


The comparison of wRC+ same side split for 2000-2005 vs. 2008-2010 is shown below.   On average, for the period 2008-2010,  the players experience a 1% increase in the reduction to their overall offense caused by batting against same side pitchers.  This seems like a relatively small impact related to aging.  However, the impacts are more intriguing if lefthand and righthand batters are separated.


On average, the lefthanded batters in the group have a 4.3% larger reduction in offense during their later years associated with same side pitchers.  On average, the righthanded batter experience a smaller reduction in offense facing same side pitchers during their later years.  Among the right handed batters, Manny Ramirez, Alex Rodriguez, and Vlad Guerrero actually hit better against RHP in the later period.  RHPs are the predominant pitchers in the majors, and it seems like these three great hitters used their experience facing them to not just improve, but eliminate the disadvantage.  Jason Bay was the only RHB in the group who showed a growing disadvantage against same arm pitchers.


During the early period (2000-2005),  all batters from both sides showed a platoon disadvantage for same side pitchers.  But the magnitude of the disadvantage was much greater for lefthand batters than righthand batters (29% vs. 3.8%).  Most of the righthanded batters improved and eliminated the disadvantage in the later years (2008-2010), but most of the lefthanded batters experienced a growing platoon disadvantage.  I realize that this is a small sample of players, and therefore I won't claim that it proves anything.  However, the distinction between the results for lefthand and righthand batters makes some sense.


How does this relate to Carlos Lee?  This small sample doesn't tell us that we should expect Lee's platoon splits to grow as he ages.  If Lee were a lefthanded batter, then perhaps our answer would be different.  Still, that doesn't mean that Lee won't take the same course as Jason Bay, a righthanded batter who experienced growing platoon splits in 2008-2010.


            Reduction in wRC+ for Same Side Platoon

2000 -

2008 -

























J.D. Drew

















Jason Bay








LHB Avg.




RHB Avg.




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