Wondering myself, but I think its more a play on the pitcher, this is what I found:
A.J. BURNETT vs. BOSTON since 1997
BURNETT is 5-0 when starting against BOSTON with an ERA of 2.56 and a WHIP of 1.154.
Not too shabby
VS.
JOSH BECKETT vs. NY YANKEES since 1997
BECKETT is 8-5 when starting against NY YANKEES with an ERA of 4.57 and a WHIP of 1.357.
:box2: See how it goes