Boxing star Jarrell "Big Baby" Miller was arrested on Tuesday ... after he was accused of body-slamming a car dealership employee before stealing a truck.
According to the Hollywood Police Department in Florida, the incident took place at Haims Motors -- a used car lot located about half an hour north of Miami.
Cops say an employee at the dealership told them a woman had approached him and complained that she had left a phone in a truck that the establishment had recently repossessed.