San Francisco 49ers defensive back Richard Sherman is never afraid to speak his mind. While numerous fans are voicing their displeasure over the new leading-with-the-head tackling rule the NFL is employing this season, Sherman has joined the chorus of naysayers. 

Here's what the rule states:

"It is a foul if a player lowers his head to initiate and make contact with his helmet against an opponent." The rule applies to all players on the field at all times, and contact does not have to be to an opponent's head or neck area; lowering the head and initiating contact to an opponent's torso, hips or lower body is also a penalty (loss of 15 yards).

Here's one example of how the controversial new rule has been enforced during the preseason:

And another:

Sherman retweeted the video of his teammate, Raheem Mostert, and challenged the creators of the rule to attempt to actually tackle someone without leading with their head.

As one fan noted, Mostert appeared to have perfect tackling form.

The NFL is looking to protect its players and combat its concussion crisis, but this new rule will likely come under fire all season.