This chart shows the passer rating for every NFL quarterback when they are not under pressure vs. when they do have pressure. It also shows the difference between the two.
Most quarterbacks are not as good under pressure, which makes sense. KC Chiefs QB Alex Smith falls right around the middle with a 104.5 QB rating with no pressure and a 68.6 QB rating with pressure.
QB rating when kept clean, when under pressure, and the change between the two. Interesting numbers: pic.twitter.com/HOV7PCRzPu— Sam Monson (@PFF_Sam) July 14, 2015
This is one of the best ways to look at the importance of the Chiefs offensive line. When they do their job, Alex Smith is a very good quarterback. Pro Football Focus rates him as one of the most accurate quarterbacks so when he is given time he can get a catchable ball to the receiver (or running back ... or tight end). The Chiefs will likely be better on the left side of the line this year while the center position and the right side are an unknown right now.
It's also interesting to see where Tom Brady lands on this list. He is obviously one of the best quarterbacks in the game and that shows with his 112 QB rating when not under pressure. But that number drops dramatically (55) when he is under pressure.