Splitter or forkball?

i grip it like a sinker with the fingers spread apart on side of ball and pressure on the bottom with my thumb. is this a splittler of forkball and will this hurt my arm. i can throw it like a fastball but when it comes out it tumbles with not much spin but i cant get it to drop. any suggestion?

forkball

I have always believed in throwing with what god gave you. Many people change there arm slot because they feel they need to start throwing side arm when they are really an over the top guy. Always stick with what you were naturally given so if you throw your fastball in a 3 quarters slot then throw your curveball or splitter the same way and you should be fine