1. Justin Fields has not shown enough yet with the Chicago Bears
It is easy to say that Justin Fields only struggled last season because of the pieces around him. However, that is simply not true. He took plenty of sacks, and fans will say it is because of the offensive line.
However, the percentage of times he took a sack under pressure was still worse than most others. He also did not work in the middle of the field, nearly ever. He had passes bounce off his receivers' hands, and he also missed passes so badly that free safeties were stunned they found a free interception.
Some fans will brush this off and say that Justin Fields was just in playmaker mode, and while he took big losses, he also was doing it to make big plays, and that did come at times. So, if he plays within the offense more because he has more time and better pass catchers, he could reduce his sacks and improve his accuracy.
Still, that is currently wishful thinking. It is easy to play both sides with Justin Fields, and no matter where you stand on the debate you could make a strong case in your favor. If you have been high on Justin Fields the entire time, nothing has swayed you. However, if you needed to be swayed hard that Fields is any good, you are probably still heading into this season with a pessimistic mindset.