Random stats: pitching platoon

Let’s examine how handedness has affected Cubs pitching.  Here are the OPS’s allowed by Cubs pitchers this year:

Righties   vs. RHB   LHB   Difference
Hart          .674 1.330     .656
Marmol        .434  .795     .361
Lieber        .732 1.082     .350
Dempster      .571  .682     .111
Marquis       .699  .785     .086
Zambrano      .622  .684     .062
Wood          .571  .629     .058
Wuertz        .741  .748     .007
Harden        .593  .589    -.004
Howry         .858  .787    -.071
Gaudin        .722  .646    -.076

Lefties    vs. RHB   LHB  Difference
Eyre          .909  .835     .074
Marshall      .722  .824    -.102
Cotts         .690  .793    -.103
Lilly         .741  .885    -.144

A positive difference indicates the pitcher has done better against same-handed hitters; a negative difference means the pitcher has done better again opposite-handed hitters.  All Cubs pitchers have been either more or less indifferent, or better against righties.