Police spokesman Steve Warneke said three males were stabbed, and a fourth may have been stabbed, but that person left the scene.
Police have several people in custody and are not looking for other suspects. None had been formally charged as of just after midnight.
Police say the incident was called in at 9:55 p.m.
Warneke described the scene as “very chaotic” and said police don't know what led up to the fight. He said police did not know whether the men had attended the game.
The Denver Post reports there were multiple witnesses.
Warneke said one person was initially in critical condition, but all are conscious and talking
Stadium Management Co. issued an email stating that it is working with authorities.
The Broncos lost 27-20 to the San Diego Chargers.
The stabbing Thursday is just one of several recent incidents involving football fans.
Earlier this month in Kansas City, Mo., a man died after an altercation in the Arrowhead Stadium parking lot during Kansas City's game against Denver.