Worst QB and worst QB that season are different.
For example Peyton Manning had some of the worst(especially considering the era) stats for a QB to win a SB for that year but no one would consider him the worst.
2015
59.8%
2249 yards(10 games)
9 TD 17 int
How many guys especially in the past 25 years were worse?
Dilfer 2000
59.2%
1502 yards(11 games)
12 TD 11 Int