We have no clue what happened, not sure why everyone assumes this guy was running his mouth and Misi went after him for that. Whatever happened Misi should have shown more discipline because he has alot more to lose. Hopefully he will learn from his mistake.
I don't think anyone is assuming anything.
http://independent.com/news/2013/feb/14/dolphins-linebacker-sentenced-isla-vista-battery/
In April 2011, authorities said, Misi punched through the front door of an Isla Vista apartment and then hit a man in the face, fracturing his orbital socket. Misi had reacted to another man yelling from the apartment balcony. Misi was arrested for the incident in March 2012.