It started when receiver Ben Obomanu and cornerback Jeremy Lane were tussling after the whistle blew on a play and had to be separated. Then safety Earl Thomas jumped in to help Lane, taking a swing at Obomanu. That led to receivers Doug Baldwin and Mike Williams jumping in to help Obomanu. (In the picture, wide receiver Deon Butler is pulling Thomas away from the fight.)
A few plays later, according to the News Tribune, safety DeShawn Shead “almost took Baldwin’s head off” on a pass over the middle.