Police say that Michael Lohan was getting into his car Thursday night when a man attacked him with a sharp object.
Lohan sustained minor cuts to his forearm and neck.
Authorities are searching for the suspect. They say that during the altercation, the attacker fell to the ground, got up and fled.
The suspect is described as a man in is 40s to 50s.
His daughter, Lindsay, was in court Friday and was ordered back into rehab for failing a drug test.