Henry Milstrey of Newark pleaded guilty to assault while a jury was deliberating his fate on Wednesday following a two-week trial.
Prosecutors say the 46-year-old Milstrey called for help and approximately 16 men assaulted 51-year-old Robert Waters in 2011. Waters, who was president of the Newark Little League, suffered a concussion and broken bone and lost a tooth during the attack.
The Essex County Prosecutor's Office says Milstrey would have faced up to 10 years in prison if he had been convicted by the jury. By entering a guilty plea, there is a presumption of no time in prison.
Sentencing is scheduled for August.