Police say Barnett was arrested after a physical altercation at the club WET in Appleton. He was taken to Outagamie County Jail and released after posting a 500-dollar bond.
N-F-L commissioner Roger Goodell has spent much of the offseason trying to crack down on off-the-field incidents involving players.
McCarthy says the Packers contacted the N-F-L about Barnett's arrest and are waiting to hear back from the league.
Barnett was absent from today's voluntary workout.