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

Julio Jones has tough Week 13 matchup (0:50)

Mike Clay explains that Julio Jones is always a must-start, but expect a down week as he faces up against Xavier Rhodes. (0:50)

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Matchups are often a driving force behind fantasy owners' weekly lineup decisions. When choosing between two (or more) similarly talented players, you know the first question that comes to mind: Which one has the best matchup?

Ah, but 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 matchup 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.

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 has held opponents at that position. All data is from the past five weeks' NFL action.

Finally, a caveat: Remember that matchups are only one ingredient in my rankings formula. Not every favorable matchup should be exploited, and not every unfavorable matchup should be avoided. To get the most complete recipe for whom to start and sit, consult my weekly rankings.