A report from ESPN claimed that members of the Ravens organisation were aware that Rice had punched his then-fiancee in the incident in February.
However, Harbaugh has insisted that Rice told him that he was only acting defensively in the melee, and never mentioned that he had punched his wife.
Harbaugh said in a statement: "Ray Rice never told me that he punched her. In June, when I spoke to ESPN The Magazine, it was still my understanding that Ray had not punched her and was acting defensively."
Ravens director of security Darren Sanders added: "Ray told me he slapped her. He denied punching her."