Always play the matchups.
Weighing matchups helps you make difficult decisions between similarly valued players, and every week, it’s important to analyze the best (and worst).
So what exactly constitutes a favorable or unfavorable matchup?
That’s where the “Matchups Map” comes in. Each week, I’ll provide a schedule-independent method to determine strength of positional matchups, using the most recent, relevant data. Check back for updated numbers each week, including matchups highlights at each position — both favorable and unfavorable — based upon those statistics. For these purposes, we will use PPR (Point Per Reception) scoring, though I have analyzed this data for both PPR and non-PPR and have found that the rankings would scarcely change (if at all). These do, therefore, help in either scoring format.
For Week 2, the maps include two measures: The first, “Rk,” is my personal ranking of how favorable/unfavorable I consider that positional matchup; the second, “Adj. FPA,” reflects how far above or below a player’s average that defense held opponents at that position. For Weeks 1-3, 2017-full-season data is used for the latter, so take those with a grain — or several grains — of salt. Beginning in Week 4, we’ll use 2018 data (three weeks in the books at that point), and then starting in Week 6, we’ll use the most recent five weeks.
Finally, a caveat: Remember that matchups are only one ingredient in my rankings formula. Not every favorable matchup should be exploited; not every unfavorable matchup should be avoided. To get the most complete recipe for whom to start and sit, consult my weekly rankings.
Source : http://www.espn.com/fantasy/football/insider/story/_/id/24660680/fantasy-football-best-worst-matchups-qb-rb-wr-more-week-2