Aaron Hernandez -- DROPPED as Spokesman for Muscle Milk

Aaron Hernandez can say goodbye to one of his sponsors -- Muscle Milk is jumping ship in the wake of the NFL star's legal troubles.

CytoSport -- the company behind the popular supplement -- said it was dropping the Patriots' tight end immediately ... in the light of the ongoing investigation.

Police searched Hernandez's Massachusetts home and the area around it ... while investigating the homicide of Odin Lloyd ... who has connections to Hernandez.

Hernandez -- who has not been arrested or named a suspect in Lloyd's death -- is also being sued for allegedly shooting a man in Miami.