Why is bubba Watson called bubba?

This is a quote from Bubba Watson regarding his name. His dad is responsible for the nickname.

Bubba on his name:

"It was in 1978, Bubba Smith was playing football. So when I was born, I was real chubby in the face and my dad wanted a baseball player and I came out chubby in the face and looked like a big football player, and he said I'm a Bubba and not-I'm a football player, not a baseball player. So 10 seconds after I was born, he just called me Bubba, and Bubba Smith was coming through. I know I missed Police Academy, but it's the same Bubba Smith, yeah."