Jermaine Edmondson and his girlfriend, Bianca Williams, filed suit July 25 in response to an altercation in July 2016 that culminated in Green allegedly striking Edmondson in the face at a restaurant in East Lansing, Michigan.
Johnson is being asked to appear because of a tweet he posted after the incident, in which he indicated he'd had a conversation with Green and that Green was very apologetic.
The subpoena asks that Johnson testify Oct. 4 at the Lakers' practice facility in Los Angeles. The documents indicated Johnson has agreed to appear.
Green, who was arrested for allegedly slapping Edmondson and faced a $500 fine and up to 90 days in jail, reached a plea deal that reduced the charges to a noise violation and a civil infraction, which carried a $500 fine and $60 in jail restitution.