Police say 22-year-old Freeman Durden, who performs as JU, had just left Club Karma on First Avenue when he was approached by five men just after 1 a.m. Authorities say one of the men gashed Durden's left cheek with a cutting object.
The men then fled the scene, and no weapon was recovered.
Detectives believe the attack could be a continuation of the rap battle that had started on stage, and they are looking into whether the five men were part of another group of performers within in the club.
Durden initially got in an Uber to take him to the hospital, but his bleeding prompted the driver to kick him out near First Avenue and East Houston Street.
He then approached local police officers to inform them of the incident, and he was taken to Bellevue Hospital in stable condition.
Police say he received 30 staples to the left side of his face.
While being treated at the hospital, detectives realized that Durden had an active warrant for criminal trespassing from 2013.
Officials say he was placed into police custody and will appear in court when able.