Best, worst matchups at all fantasy football positions for Week 13

Should fantasy managers still start Andrews? (1:07)

With Mark Andrews' performance slowing down recently, Field Yates and Matthew Berry break down what this means for the Ravens TE in fantasy. (1:07)

Matchups play a huge part in fantasy football managers' weekly lineup decisions. When choosing between two (or more) similarly talented players, the decision often boils down to: Which one has the best matchup?

We use that word -- matchup -- a lot. But what, exactly, constitutes a favorable or unfavorable matchup?

This is 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 matchup highlights at each position -- both favorable and unfavorable -- based on those statistics. For these purposes, we will use PPR (point per reception) scoring.

The maps include two measures: The first, "Rk," is my 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. All data is from the past five weeks' NFL action.

Finally, a caveat: 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.