The four worst completion percentages in the NFL among qualified QBs:
Mayfield - 57.8
Darnold - 56.1
Rosen - 55.0
Allen - 54.0
The four worst passer ratings in the NFL among qualified QBs:
Mayfield - 78.5 (Mariota is tied - he really sucks too)
Darnold - 74.3
Rosen - 66.0
Allen - 61.8
I've noticed a lot of Jete fans are down to comparing Darnold to the other three rookies as some kind of measuring stick. But it seems like a strong possibility that this class is just terrible and perhaps historically bad. They may be rookies, but they are easily the worst in the league, and the game has changed a lot in the modern era, where this type of horrendous start is not just a matter of growing pains but an answer as to whether or not they will make it.
Clipboards can't carry themselves though. There are some backup/third-string spots that will welcome these guys with open arms. My guess is the Bills, Browns, and Cardinals will figure it out and move on by the end of next year. The Jets will double down and probably offer Darnold a massive extension like they did with Sanchez. I'd say the next window of hope for the Jets is around 2026 or so.