Police said security guards at The Flats on Carson summoned a police officer who was working at a nearby restaurant "due to an unruly customer who was in the process of assaulting the doorman.''
Police said the officer stopped the assault and arrested the customer, who was later identified as Porter, 39, a former star player.
Porter was taken to the Allegheny County Jail. He is charged with aggravated assault, simple assault, resisting arrest, public drunkenness and disorderly conduct. It is unclear if he has an attorney who can comment on the charges.
The Steelers acknowledged an "incident involving Joey Porter" in a brief statement Sunday.
"We are still gathering information as it pertains to the situation, and we will have no further comment until we get more details," team spokesman Burt Lauten said.
Porter, who played eight of his 13 NFL seasons in Pittsburgh, is in his second season as the Steelers' outside linebackers coach.
Porter has had multiple run-ins with the law in the past, including a 2010 arrest for suspicion of drunken driving and an accusation of assaulting a police officer and resisting arrest. Those charges, filed in his hometown of Bakersfield, California, were eventually dropped.
The Steelers will visit the Kansas City Chiefs next Sunday in the divisional round of the playoffs.
Information from The Associated Press was used in this report.