This, and the fact that he has the weakest offensive supporting cast of the 4 rookie QB's, is the critical piece of information in understanding why Allen is the least impressive of the 4 rookies. To take it a step further in the two & half games Rosen has played in he has faced the #7, #12 & #17 defenses. Darnold has had it even easier facing the #2, #18, #23, #25, #27 & #28 ranked defenses!
Sure, playing Buffalo helped the defenses out but with 6 games in the bag the sample size is big enough to say with confidence that Allen has faced the toughest defensive competition of the little three rookies (we can all admit that Mayfield was a step above the other 3).