Yeah, it's tough.
I try to only select players who have a clearly defined role in the same team with the same coach and QB as the previous year.
I started with Hall because he filled all those criteria.
His role hasn't really changed: 13 carries a game this year vs 13.1 last year; 5.6 targets per game this year vs 5.6 last year.
What is different, so far, is his "form": only 3.0 ypc on average compared to 4.5 and 5.8 in previous seasons.
But as I posted last week, Hall can have multiple consecutive weeks with a low ypc figure. He makes up for those games with games where he can average up to 8.0 ypc and more.
However, almost every player is affected by match-ups and I try to start/bench players according to their match-ups.
This week Hall was up against Minnesota: they have the 2nd best run defence allowing only 67.2 ypg; they have the 3rd worst pass defence allowing 263 ypg
It shouldn't have been a great surprise that the Jets had 54 pass attempts to only 14 carries.
I pay far more attention to match-ups than most of the pundits seem to do.
Although it isn't that straightforward. Other factors come in to play: recent form; is a RB involved in the passing game; are they playing at home or away; what injuries does their team have - these are the ones I see as most important.
I must admit, it takes research and I know not everyone has the time.
ESPN has the team defence stat.s:
https://www.espn.com/nfl/stats/team/_/view/defense/table/passing/sort/netPassingYardsPerGame/dir/asc