Matchups matter in fantasy football. They are also probably overvalued, because knowing which ones will continue to be good or poor matchups can change over the course of a season due to game flow, injuries, and luck. If you are fortunate enough to be in a good position after week 5, you may be tempted to look ahead and set some matchups with trades and transactions.
I went back through the previous five seasons to look at defensive stats through the first five games for each team, and compare them to the defensive stats during weeks 14 to 16, which tend to be when the fantasy playoffs take place. I ran correlations of various stats to see how predictable the future was, knowing the results of five weeks of games.
The answer: not very.
And another surprising answer: the “best” way to play matchups, if you choose to do so, is rushing fantasy points in the playoffs, based on bad pass defense early.
Last year, the team that had allowed the most passing touchdowns through 5 weeks was the Chiefs (13). They allowed 12 for the rest of the year, and were a bad matchup in the playoffs. The last five years is full of almost as many counter-examples as it is teams that continued to be good matchup plays.
Here are the results for week 14-16 fantasy points, isolating the best correlation coefficients (in terms of distance from zero):
If you need a refresher on correlation coefficients, a coefficient of “1” equals a perfect direct relationship, a coefficient of “-1” would represent an inverse relationship, and one near zero would be little or no relationship.
None of the stats measured had a strong relationship to future passing fantasy points allowed at the end of the season. There is too much noise and contradicting examples.
That’s not true for the rushing stats allowed, though it’s not related to the rush defense, but pass defense at the start of the season.
The best measure to try to predict future rushing yards allowed in weeks 14 to 16 has been Net Yards per Pass Attempt Allowed in the first five weeks. It’s not perfect, or particularly strong, but it’s strong enough to matter more than things you might think, like rushing yards allowed and rushing fantasy points allowed. (That correlation coefficient was +0.15). For some comparison, the year-to-year win correlation for NFL teams is in the +0.30 to +0.40 range.
If you were to try to guess the teams to play against in terms of rushing production, the best guess would be to go with the following:
New York Jets
While you may say, well, yeah, those aren’t dominant defenses this year, they don’t currently rank near the bottom in rushing yards allowed.