Generally speaking, fantasy analysts are very good at accounting for strength-of-schedule when looking at future matchups, yet we tend to ignore it when describing past performances. I'm not sure why that is, but it's true.
You might hear an expert say something like this...
"Eli Manning is the No. 24 fantasy quarterback over the past four weeks" (which he is)
...but it's rare that we provide context like this...
"In three of his last four games, Eli has faced defenses that rank top-five against the pass." (Also true: SF, Dal, Pit).
So we're matchup advocates when forecasting, and we're matchup agnostics after the fact.
Again, I can't really explain why this is the case. It probably has something to do with the limitations of the analytical tools we're all using.
As a fantasy gamer, you simply need to recognize buying and selling opportunities when they arise. Right now, in Eli's case, I'd say there's a window to buy low. He's been a multi-week fantasy disappointment while facing a murderous schedule, and many owners are bailing. No one cares that he had a 510-yard game earlier this season, nor that he delivered the sixth-best yardage total in league history just last year. Manning is slumping, so people are selling.
If you'll look ahead, however, you'll note that each of Eli's next four opponents rank in the bottom-half of the NFL in pass defense. Cincinnati is 19th (240.4 YPG), Green Bay is 20th (243.6), Washington is 31st (301.7) and New Orleans is 29th (294.8).
Prediction: By mid-December, when the fantasy playoffs are getting underway, Eli will have returned to the circle of trust. He'll be riding a hot streak, a consensus top-8 play. Add now if you can, if you have a need.