Manchester City say they are "shocked and appalled" at abuse suffered by Phil Foden and his family backstage at Saturday's Amir Khan-Kell Brook fight.
Footage has emerged on social media of a confrontation at Manchester Arena between members of the public and a group including the England midfielder.
Greater Manchester Police say they have received no report of the incident.
City said they were aware of a video that "shows Phil Foden and his family being harassed and abused".
"We are shocked and appalled about the nature of the abuse and ensuing assault on one of Phil's family members," their statement added.
"We will continue to give Phil and his family all the support and assistance they need."