for LHB: (.057*1000+Split*PA)/(1000+PA)
For RHB: (-0.037*1000+Split*PA)/(1000+PA)
For Switch (n/a here): (Split*PA)/(1000+PA)
Obviously, very limited, and teams can parse things to pitch type, weather, time of day, pitcher ground/fly tendencies, you name it, but handedness of the pitcher is the biggest one.