Wednesday, February 3, 2010

Revisiting Age Associated Decline of NFL Players for Fantasy Purposes

When do players in the NFL decline? At what age do NFL players generally decline at each position? These are important questions for fantasy players.

Doug Drinen (How Important is Age?) summarizes his research: "According to this data, the word 'old' means 28 for a running back, 30 for a receiver, and 32 for a quarterback. This is probably not a surprise, as it squares fairly well with conventional wisdom." UPDATE (4/6/10) Do star safeties have shorter careers than players at other defensive positions?

Boy am I glad someone has already crunched and published those numbers.

This does not mean there are not anomalies. For some reason D Mason WR performed above average after 30. We all know some elite QBs like the Warners and Favres of this world also performed well after the normal age of decline (32). Likewise, there are exceptional RBs who performed well after the peak years (e.g., T Barber). There may be other factors at play like the health and effectiveness of an offensive line or the number of carries prior to the years of decline. This is one of those proverbial rules where this is the general norm but not supposed to explain all exceptions. It is helpful to the fantasy player in general but it should not be the end all reason for no longer drafting or keeping T Brady or P Manning etc. But this is also not sensitive to when players begin to peak. For instance WRs usually don't have a breakout year until their 3d year in the league. Same goes with QBs. Their breakout year usually is not their first year in the league. It also depends on how long they have or may not have been a backup before acquiring the starter status. Regardless, this is the gnomic or customary guideline of ages for understanding the decline of NFL players at these positions.

Taking Drinen's research into consideration I want to revisit the age of the players on the final rosters of the fantasy teams in Brothers Keeper. On a previous post I showed the general average age of each team's players for the 2010 season excluding Kickers and Defenses for obvious reasons (by the way I sure hope the Ravens pick up Matt Stover). Here are the results again (noting that they are not position specific, rather, they are overall age of players divided by number of players on the fantasy team):

Team                              Avg Age
Yer X-MOM                     25.87
Yankinfowlsandfeline      26.64
Sea Buzzards                  27.25
Ghost                            27.46
CustodianPandemonium  27.54
Simba's ButtKicker!         27.69
Redmans CatPunters       27.83
Favre$Footlong               27.92
Cyborg Pirate Ninjas       28
Kabuki Strikes Back        29.46

If, however, we use the age of decline for each position as a baseline (negative numbers are good!) and we total up the years above or below the baseline we get these results:

Team                           Total Years Above/Below Age of Decline
Yer X-MOM (P Smith)                                   -50
Yankinfowlsandfeline (J Smith)                     -31
Ghost (B Garner)                                         -27
CustodianPandemonium (R Smith)                -25
Sea Buzzards (M Peltonen)                           -24
Simba's ButtKicker! (R Johnson)                   -23
Favre$Footlong (D Kessler)                          -21
Redmans CatPunters (D Pilcher)                   -18
CYBORG PIRATE NINJAS (R Smith)                -16
Kabuki Strikes Back (J Fullerton)                     2

In order to eliminate the variation of numbers of players on each team here is the average of the previous list:

Team                      Average Years Above/Below Age of Decline
Yer X-MOM (P Smith)                                  -3.33
Yankinfowlsandfeline (J Smith)                    -2.82
Ghost (B Garner)                                        -2.08
Sea Buzzards (M Peltonen)                          -2
CustodianPandemonium (R Smith)               -1.92
Simba's ButtKicker! (R Johnson)                  -1.77
Favre$Footlong (D Kessler)                         -1.62
Redmans CatPunters (D Pilcher)                  -1.5
CYBORG PIRATE NINJAS (R Smith)               -1.23
Kabuki Strikes Back (J Fullerton)                  0.15

These stats are only helpful to understand who may or may not be as poised to make a long term impact in Brothers Keeper from the available players on the final rosters of 2009. Those at the top of the lists have a better chance of retaining talent below the normal age of decline than those at the bottom of the lists. While it may be more probable, it is still possible for a team like Favre$Footlong to keep players that are older than Kabuki Strikes Back might keep and therefore these lists are in no way a final predictor of fantasy success in the long term.

A few caveats are also necessary. This does not account for future NFL strength of schedule and other factors like offensive linemen turnover/age/effectiveness. This should not directly correlate to fantasy points. It does not factor in over usage of players who may burn out faster. This may have some correlation to injuries but not entirely as some injuries are entirely random. This is merely a snapshot in time of how young the current fantasy rosters are and a small projection of the probability of keeping talent below the age of decline. Some teams are more able to keep players younger than the declining ages than other fantasy teams.

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