Earlier this month, we added several new statistics reports to the site, a few of which specialize in performance splits, compiling batter performance against righties and lefties, pitcher performance in platoon splits as well, and the numbers accrued for each group at home and on the road. I outlined how to use the reports and the types of information they contain last week, but with awards season in full bloom, it felt like the perfect time to delve into the various facets of platoon splits and crown a few winners of our own. Some of the numbers I will use here are not yet on the actual reports, the same of which can be said for the handedness of the individual subjects being split, but they will certainly be incorporated in the near future.

Before moving on, perhaps a brief review of platoon splits-mainly their purpose and what should be gleaned from their usage-is in order, much of which is fleshed out in an article I penned back in July titled Contextual Platooning. It’s well understood that hitters perform worse against their same-handed brethren than they do when opposed by pitchers of the opposite hand, the effects of which are more pronounced for lefties, given that southpaws only account for approximately one-quarter of a batter’s plate appearance in a given season. With the recent prominence of lefty specialists, that percentage of total plate appearances could rise, but it tends to hover right around this mark. Therefore, when evaluating how a batter performed, we cannot measure him in relation to himself if the goal is to be, well, accurate. Instead, we must compare his performance in a split component to the average performance in that specific split.

That summer article focused primarily on Ryan Howard, noting how his 2006-08 Raw EqA was better than or right in line with the league-average Raw EqA for hitters against same-handed pitchers. Extending that idea, each of the four splits carries their own averages, which will serve as the comparative basis for individual performance in this evaluation. It’s very important to remember that the utility of platoon-split performance is limited due to the small samples of plate appearances under investigation each season as well as the innate fickleness. The data is interesting, but decisions about a guy’s talent level should not be made on the basis of, say, Randy Ruiz‘s 100 plate appearances against righties this past season, just as too much pride should not be invested in how effectively Raul Ibanez tore apart fellow left-handers in his 167 trips to the dish this season.

With that out of the way, the methodology here was rather simple: calculate the REqA for each player against both types of pitchers, calculate the weighted average REqA for the four different splits (RR, RL, LR, LL), and use the delta from individual to average as a means of issuing rank. For splits involving left-handed pitchers, the minimum amount of plate appearances was set to 100, while it rose to 275 when righties were on the mound. Without further ado, here are the ten best righties this past season with fellow righties toeing the rubber:

                Bats                                  REqA
Hitter         vs. RHP    PA     AVG    OBP    SLG   Delta
Albert Pujols     R      515    .324   .435   .645    .326
Hanley Ramirez    R      478    .352   .423   .591    .271
Derrek Lee        R      498    .308   .382   .604    .234
Kevin Youkilis    R      418    .304   .404   .560    .228
Manny Ramirez     R      344    .295   .427   .536    .222
Matt Holliday     R      485    .322   .390   .555    .207
Troy Tulowitzki   R      442    .307   .376   .566    .200
Alex Rodriguez    R      388    .289   .402   .529    .192
Miguel Cabrera    R      508    .327   .380   .556    .191
Ryan Zimmerman    R      533    .298   .361   .545    .166

This seems like the usual suspects as far as this writer is concerned. Well, aside from maybe Derrek Lee, who appeared to be on the schneid for the last couple of seasons to everyone outside of Chi-town. Lee also came closest to Pujols in terms of his ISO, with a .296 to Albert’s .321, while the rest of the Big Ten members ranged from Cabrera’s .229 to Tulo’s .259.

Who made up the bottom five in this particular split last season? In order from least to most putrid: Rod Barajas, Adrian Beltre, Gerald Laird, Willy Taveras and, you guessed it, Yuniesky Betancourt. Take the same group of batters but flip the pitchers around and the following fearsome ten surfaces:

                Bats                                  REqA
Hitter         vs. LHP    PA     AVG    OBP    SLG   Delta
Justin Upton      R      137    .377   .445   .762    .393
Ryan Braun        R      141    .395   .475   .723    .384
David Wright      R      133    .416   .496   .646    .338
Albert Pujols     R      185    .338   .465   .696    .338
Matt Diaz         R      152    .412   .464   .640    .318
Jayson Werth      R      188    .302   .436   .644    .270
Scott Rolen       R      135    .374   .459   .591    .263
Matt Kemp         R      154    .362   .429   .616    .246
Ben Zobrist       R      201    .319   .440   .595    .239
Pablo Sandoval    R      159    .379   .428   .600    .239

Upton’s delta of .393 not only led this group but topped everyone in any platoon split in 2009, and he ranks in a tie for 36th place amongst this particular split since 1954 with Manny Ramirez back in the 2000 season. Notable here are the batting averages-“Aaahh, he is using batting averages for something!“-of David Wright and Matt Diaz, both of whom topped .400, with Braun falling just short at .395. Speaking of the Hebrew Hammer, his .384 delta in this split ranked second to Upton last year, and ranks 45th since 1954 in this split, settled between Nomar Garciaparra‘s 1999 and the 1959 campaign of Willie Mays.

Randy Winn ranked at the bottom in this category and, quite frankly, had little competition. In 125 plate appearances against lefties, he hit a measly .158/.184/.200, for a REqA delta of -.386. Second place was Willy Taveras at -.255 for comparison. Winn’s season ranks as the worst RHB vs. LHP performance since 1954, barely worsting Luis Matos‘s -.381 delta during the 2004 season.

Moving on to the other opposite-handed split:

                Bats                                  REqA
Hitter         vs. RHP    PA     AVG    OBP    SLG   Delta
Joe Mauer         L      383    .377   .462   .641    .294
Ryan Howard       L      451    .320   .395   .693    .279
Adrian Gonzalez   L      427    .305   .448   .629    .263
Prince Fielder    L      521    .303   .432   .610    .239
Jason Kubel       L      414    .322   .396   .617    .210
Joey Votto        L      384    .319   .419   .583    .201
Adam Lind         L      475    .317   .389   .602    .196
Todd Helton       L      439    .332   .437   .548    .192
Lance Berkman     L      415    .291   .436   .546    .185
Adam Dunn         L      500    .267   .414   .564    .177

Mauer certainly raked against righties, but as you’ll find, an equally important component to his success will be on display in the very next table. His .294 delta ties old Cincinnati Redlegs catcher Ed Bailey‘s split in the 1956 season for 49th in LHB vs. RHP data in the Retrosheet era. One caveat to make that seem more impressive: the delta for Ryan Howard’s MVP season in 2006 in this regard ranks 79th, a full 30 slots behind Mauer’s ’09 season. I think it was fairly evident that he could handle himself against righties. Cesar Izturis and his -.193 delta worsted all others in this area, a mark that ranks 4499th out of 4528 in the 55-year span being queried.

And now the toughest of all splits:

                Bats                                  REqA
Hitter         vs. LHP    PA     AVG    OBP    SLG   Delta
Raul Ibanez       L      167    .285   .359   .639    .277
Chase Utley       L      235    .288   .417   .545    .248
Hideki Matsui     L      148    .282   .358   .618    .246
Prince Fielder    L      198    .292   .359   .584    .225
Joey Votto        L      160    .329   .400   .531    .211
Joe Mauer         L      223    .345   .413   .497    .196
Nick Johnson      L      166    .316   .440   .444    .185
Josh Hamilton     L      119    .327   .361   .536    .184
Denard Span       L      214    .330   .405   .473    .175

I can’t say that I expected to see Ibanez top off this list, or two consecutive Phillies for that matter. Ibanez’s split above actually resulted in the 27th-best delta since 1954. Ryan Howard may be a mere mortal with southpaws on the hill, but the presence of Ibanez, Utley, and Werth certainly made the back-to-back NL pennant winners a formidable foe for lefties. The worst lefty against his like-handed opponents was Gerardo Parra, who hit .220/.250/.220 in 106 plate appearances, a -.233 delta that ranks 2,186th among 2,197 qualifiers in the same span.

Relative to understanding the purpose of platoons, the standard has always been to evaluate the contra, how someone performs relative to himself, but as we discussed over the summer, this is not an accurate basis for making decisions. Knowing that Vernon Wells was below average against opposite-handed pitchers while ever so slightly above average on the same handed front is much more valuable than the actual numbers, since the individuals themselves are inappropriate baselines. To get really granular, we could bin the players based on their skill sets and use that mean as the basis for comparison. With any split, though, I cannot stress enough that the league average is necessary for issuing judgments, while the contra is not nearly as important, especially with the small sample sizes.

Still, the point here was to give out the 2009 Platoon Split Awards, and our same-handed winners are Albert Pujols (RHB vs. RHP), Raul Ibanez (LHB vs. LHP), with opposite-handed winners being Justin Upton (RHB vs. LHP) and Joe Mauer (LHB vs. RHP). If those four serve as the equivalent of division winners in a playoff style format, then Ibanez and Pujols advance to the championship, given that their respective historical rankings in the specific splits in question. Since Ibanez ranked 27th, and Pujols’s .326 delta ranks 17th amongst righty versus righty splits since 1954, Fat Albert comes away with another trophy for his mantle.

Thank you for reading

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I would say his mantel better deserves the trophy.
I'm revealing my ignorance, but what is "delta".

It sure would be helpful if it was defined somewhere.
Delta in this instance means the difference, or change, from one to the next. So when I say REqA Delta I am referring to the REqA of the individual in relation to the average for the league for that split.
Considering Parra had such terrible results against Lefties, but had a solid season overall (he hit righties to the tune of .310 / .345 / .456 over 355 AB, why not platoon him with Chris Young who hit .262 / .406 / .514 against Southpaws?
Considering the overcrowded nature of that OF going forward, this might be a nice platoon even thought it drastically undercuts C.Young's ceiling.