Fields is a running qb, Rodgers, at this point of his career, really isn't. So to me, the difference is that as a defender you are expecting Rodgers to go down well before it got close so if a defender were to hit him in the head it would more likely be with intent. On this play, fields was juking and in the middle went for the slide. Douglas, trying stick with him is starting to go down to his left and starts to lower his head for the tackle(where he makes his mistake) as fields is starting his slide. Obviously the slide brings fields head even with Douglas' head and it looks bad. I would also say it looks like Douglas did do what he could to avoid hitting him with his helmet, but still made contact. Why I don't think it should have been a penalty is because I don't feel like he had enough time to avoid contact based on his momentum after the start of the slide. He's a running quarterback and it would be stupid for the defender to expect a slide there.