Fletcher Cox had zero tackles, zero assists and zero sacks in the game against the Atlanta Falcons. That makes you ask the question of whether he is giving his best effort or not.
I checked out the tape and Cox is being double-teamed. That is opening up opportunities for his teammates, but Fletcher shouldn't be taking those plays off.
He needs to attack one of the O linemen blocking him in the same way Aaron Donald of the Rams does. Fletcher is so powerful he can attack one of the offensive linemen, blow him back and still be a factor in the play.
I understand that he will get tired at times. That's fine, but he shouldn't be taking plays off.
He almost got a couple of sacks in that game. He's still a great player and he should give the team all he has when he's on the field.