Law 12: FOULS AND MISCONDUCT
SERIOUS FOUL PLAY
A tackle or challenge that endangers the safety of an opponent or uses excessive force or brutality must be sanctioned as serious foul play.
Any player who lunges at an opponent in challenging for the ball from the front, from the side or from behind using one or both legs, with excessive force or endangers the safety of an opponent is guilty of serious foul play.
VIOLENT CONDUCT
Violent conduct is when a player uses or attempts to use excessive force or brutality against an opponent when not challenging for the ball, or against a team-mate, team official, match official, spectator or any other person, regardless of whether contact is made.
In addition, a player who, when not challenging for the ball, deliberately strikes an opponent or any other person on the head or face with the hand or arm, is guilty of violent conduct unless the force used was negligible.
Violent conduct is when a player uses or attempts to use excessive force or brutality against an opponent when not challenging for the ball.
Trippier attempted to use excessive force when not challenging for the ball.
Made no attempt to get the ball.
Only aim was to stop KDB.
Knee height brutality.
RED CARD