New Orleans Pelicans center Jaxson Hayes -- the #8 overall pick in the 2019 NBA Draft -- was arrested after an alleged violent altercation with police, TMZ Sports has learned ... and it apparently got so extreme, the hooper and a cop were taken to a hospital.

We're told law enforcement were called to an LA area home for a domestic disturbance early Wednesday morning ... and when cops attempted to check on the parties involved, 21-year-old Hayes tried like hell to keep them from entering the premises.

Sources tell us 6'11", 220-lb. Hayes got combative with cops and a fight broke out ... with the ex-Texas Longhorns star getting tased in the middle of the scuffle.