Like it's totally fine to say, "well Denver's defense is an NFL defense so any good performance against them is a positive." Totally fine. But if you say that, then you can't handwave Bagent's success because it happened against bad teams - those are NFL teams, so by your own logic any good performance against them should be considered a positive.
It's also totally fine to say, "well Bagent won two but they were against bad teams so they don't count that much." Totally fine, but if you say that then you can't continue to point to Fields' two performances against bad defenses as evidence to keep him - those were bad teams, so by your own logic any good performance against them shouldn't count that much.
What you're trying to do is hold both things simultaneously depending on which one confirms your bias. Bagent won two but they don't count much because they were against bad teams; Fields had two great games and sure they were against bad defenses but these are NFL players, any good performance against them is great.