Barnes allegedly confronted Fisher at the home of his estranged wife, Gloria Govan, and the two got into a physical altercation, according to the New York Post.
Barnes later said that he received a concerning text from his son, who has at the house with Govan and Fisher, and went to see what was wrong. He did not address the details of what happened.
Barned allegedly punched Fisher in the face. Fisher did not press charges.
Barnes is averaging 25.6 minutes, 8.6 points and 5.0 rebounds this season.
The Grizzlies (17–16) play the Miami Heat (18–11) on Tuesday.