4. Feel vs pressure
This is essentially the same process issue, but if you think that teams need to send seven men to beat Fields, there are other alleys. The biggest is stunting and twisting. As noted, the biggest issue is that when what he expects is not what he sees he gets flustered.
Check out this play against Nebraska. The left guard gets beat clean, but notice the movement. One man showing blitz on the right drops, and a man stunts from over the left tackle to over the right side. Fields is reacting to this when he sees his man beat. His movement is almost more robotic than based on feel.
Again, they do blitz here, but the issue that gets home is the stunt. This can also be an issue for the offensive line, but once again you can see that he is not anticipating pressure. He had room to his right, but his eyes were downfield and he was not feeling the pressure to his left.
Once again, they bring five, but the stunt throws Fields off. He has a man in the short flat but he hesitates with the pressure coming in. This leads to a sack that could have been avoided. According to PFF, 25% of the time he faced pressure, it resulted in a sack. That is the worst in the draft class. It is a different sport altogether, but Trubisky had a 21% pressure to sack rate last year, which was pretty high as well..
This one is not even a stunt, but once again the left guard loses and Fields struggles to feel the pressure. His line is not helping on most of these occasions. Still, Fields needs to be able to avoid converting so many pressure spots into sacks.
There are plenty of occasions where you can see him work through muddy pockets and step up in the pocket when needed. These are not primary examples, and you can see in his footwork that he can improve in this area, but these are probably conversations teams are having about Fields.