Hayes extended his left arm and fouled Milwaukee center Drew Gooden in the second quarter Thursday night. His arm seemed to get tangled with Gooden and his shoulder popped out.
Hayes lay on the floor writhing in pain for a few minutes, the arena falling so silent that his screams could be heard from the sideline. He walked off under his own power holding his arm.
A Kings spokesman confirmed Hayes dislocated his left shoulder.
The team previously said a heart exam on Hayes showed an abnormality that would require further testing and voided the contract he signed in December. A few days later, the forward-center agreed to a new deal with Sacramento.