Fantasy football Week 4: Best and worst matchups at each position

Dameon Pierce is quickly becoming a fantasy force. Daniel Bartel-USA TODAY Sports

Making those tough lineup decisions, week over week, can be the most challenging part of the fantasy football process. When you're torn between two similar players, and simply don't know which of them to start, my advice is to start the player with the superior matchup.

Ah, but exactly how does one determine the best (and worst) weekly NFL matchups?

The "Matchups Map" each week provides a schedule-independent method to evaluate positional matchups, ranking all 32 opposing defenses in order of most to least favorable for opposing players at all four skill positions (quarterback, running back, wide receiver and tight end). Instead of relying upon seasonal totals, in this space we calibrate points-allowed data to show how each defense fared relative to the difficulty of the schedule that it has faced. This provides a fairer approach to judging the quality of individual matchups.

For Week 4, these maps include two measures: The first, "Rk," is my personal ranking of the matchup; the second, "Adj. FPA," reflects how far above or below players' weekly PPR fantasy point averages that defense held opponents at that position in 2021. Remember, teams often use multiple running backs and wide receivers in a game, and these plus/minus averages cover all of a team's personnel at that position.

The reason for using my personal rankings right now, rather than year-to-date totals, is that two weeks' worth of defensive numbers don't provide an adequate sample with which to judge performance. Once three weeks are in the books, we'll begin using 2022 data as well as my personal rankings to adjust for the still-limited sample, then beginning in Week 6 (five weeks in the books), we'll rank only by what the numbers say, and each subsequent week will provide a snapshot of the most recent five weeks.

A couple of caveats before we start: Take the 2021 data with a heaping dose of salt, as the rankings are much more important. Additionally, matchups are only one ingredient to the lineup-setting process, as not every favorable matchup should be exploited, nor unfavorable matchup avoided. If you want my -- and ESPN fantasy staff's -- most complete source for whom to start and sit each week, consult our weekly rankings.