• Pass interference replay: Offensive and defensive pass interference calls are reviewable. Plays can be reviewed whether the penalty was called on the field or not. A pass interference ruling will be changed in replay only when there is clear and obvious visual evidence that the on-field ruling was incorrect. To change the ruling on the field, there must be clear and obvious evidence that contact “significantly hindered” or “did not significantly hinder” an opponent.

• Blindside block: It is now prohibited for a blocker to initiate forcible contact with his head, shoulder or forearm when his path is toward or parallel to his own end line. The penalty for an illegal blindside block is a loss of 15 yards and a loss of down.

• Kickoff rules: Changes that were implemented for the 2018 season became permanent.

• Booth review additions: If a penalty flag is thrown that would negate a touchdown, the play will be reviewed first to determine if there was a score before the defense elects to enforce the foul. And two-point conversion reviews will now be initiated by the replay official, not a coach’s challenge.

• Celebrations: Only players in uniform may enter the field to celebrate. If anyone other than a player in uniform enters the field, it is a penalty for unsportsmanlike conduct — loss of 15 yards and an automatic first down.

• Player disqualifications: In 2018, designated members of the officiating team could disqualify a player for non-football acts if a flag was thrown related to that act. In 2019, this will be expanded to also include any football act.

• Offensive holding: Offensive holding will be more strictly enforced this season, particularly on the back side of the run play or line of scrimmage. Material restrictions include grabbing or tackling an opponent; hooking, jerking, twisting, or turning him; pulling him to the ground.