NFL

Carson Palmer Does Not Have History on His Side

Sal Cacciatore  —  @SCacc8 Oct 5th, 2016
Quarterbacks who have a great season in their late 30s tend to decline the following year. Will Palmer continue this trend?

The 2016 season has not been kind to Arizona Cardinals quarterback Carson Palmer.

Palmer’s completion, touchdown, and interception rates are below the league average, he suffered a concussion on Sunday that puts his status for Thursday’s game in doubt. To top it off, Arizona is just 1-3.

The rough start comes on the heels of a career year for Palmer in 2015, when he threw for more than 4,600 yards and 35 touchdowns, while leading the league in net yards per pass and Passing Net Expected Points (you can read more about NEP here).

When viewed in this light, his current struggles are surprising, but should we have seen them coming?

Palmer's 2015

It seems easy to ask this now, but if Palmer turns things around, this success would buck a trend for aging quarterbacks, even good ones.

During his age-36 season last year, Palmer set career highs in raw yards per attempt, net yards per attempt, and adjusted yards per attempt both in standard form and relative to league average. His 6.5% touchdown rate was also the best of his career (and second-best of his career relative to league average).

In terms of advanced stats, Palmer also set career bests in terms of Passing NEP and Passing NEP per drop back. His 52.9% Passing Success Rate was the second-best mark of his career, narrowly trailing his 53.1% rate from 2005 (Success Rate is the percentage of plays that yield positive NEP).

All this success at an old age (for a football player, at least), put Palmer in rare company, as his 2015 season marked the 47th time a quarterback threw at least 200 passes and posted an adjusted yards per attempt rate that was at least a standard deviation above league average, according to Pro Football Reference (there have been 171 total seasons in which a quarterback who is 35 or older has attempted at least 200 passes).

Adjusted yards per attempt takes raw yards per attempt and gives a 20-yard bonus for touchdown passes and a 45-yard penalty for interceptions (it is inferior to adjusted net yards per pass because it does not include sack yardage; however, sacks were not tracked until the 1970s, so AY/A is useful here because it allows us to look at all of NFL history).

Before we go on, make sure you’re paying attention New England Patriots fans -- because Tom Brady joined this group last season as well.

The Following Year

37 of these quarterbacks returned the following year to throw at least 140 passes, and things generally did not go well for this group. In the seasons in which they were at least a standard deviation better than the mean, this group had an average AY/A+ of 121.9; the following year, their average AY/A+ fell to 105.4 (AY/A+ is adjusted net yards per pass relative to league average, in which 100 is always average and 15 units equal one standard deviation above or below the mean).

Only eight of these quarterbacks saw their AY/A+ increase, while 19 saw a decline of more than one standard deviation, and nine fell by at least two. Peyton Manning (last year) and Y.A. Tittle (1964) fell by more than three standard deviations, suggesting all-time greats are not exceptions here.

Here is the group:

Player Year Age Tm Year
Att 		Year
AY/A+ 		Y+1
Att 		Y+1
AY/A+ 		AY/A+
Diff
Randall Cunningham 1998 35 MIN 425 136 200 104 -32
Peyton Manning 2013 37 DEN 659 134 597 116 -18
Steve Young 1997 36 SFO 356 133 517 126 -7
Dave Krieg 1994 36 DET 212 132 521 93 -39
Steve DeBerg 1990 36 KAN 444 132 434 101 -31
Y.A. Tittle 1963 37 NYG 367 131 281 73 -58
Roger Staubach 1978 36 DAL 413 128 461 133 5
John Brodie 1970 35 SFO 378 126 387 98 -28
Rich Gannon 2002 37 OAK 618 126 225 90 -36
Brett Favre 2009 40 MIN 531 125 358 85 -40
Charley Johnson 1974 36 DEN 244 125 142 90 -35
Y.A. Tittle 1962 36 NYG 375 124 367 131 7
Steve Young 1996 35 SFO 316 124 356 133 9
Len Dawson 1971 36 KAN 301 124 305 100 -24
Tobin Rote 1963 35 SDG 286 124 163 87 -37
Roger Staubach 1977 35 DAL 361 123 413 128 5
Phil Simms 1990 35 NYG 311 122 141 111 -11
Peyton Manning 2012 36 DEN 583 121 659 134 13
Fran Tarkenton 1976 36 MIN 412 121 258 99 -22
Dan Marino 1996 35 MIA 373 119 548 106 -13
Doug Flutie 2000 38 BUF 231 119 521 94 -25
Jeff Garcia 2007 37 TAM 327 119 376 109 -10
Rich Gannon 2000 35 OAK 473 118 549 116 -2
Tom Brady 2012 35 NWE 637 117 628 101 -16
Brett Favre 2007 38 GNB 535 117 522 90 -27
Billy Kilmer 1974 35 WAS 234 117 346 111 -6
Trent Green 2005 35 KAN 507 117 198 90 -27
Rich Gannon 2001 36 OAK 549 116 618 126 10
John Elway 1995 35 DEN 542 116 466 113 -3
Fran Tarkenton 1975 35 MIN 425 116 412 121 5
Peyton Manning 2014 38 DEN 597 116 313 68 -48
Sammy Baugh 1949 35 WAS 255 116 166 106 -10
Kurt Warner 2008 37 ARI 598 115 513 107 -8
Doug Flutie 1998 36 BUF 354 115 478 98 -17
Craig Morton 1978 35 DEN 267 115 370 102 -13
John Elway 1997 37 DEN 502 115 356 120 5
Warren Moon 1995 39 MIN 606 115 247 90 -25
AVERAGE 121.9 105.4 -16.5
MEDIAN 121 104 -16


The picture may be even bleaker for Palmer though. We can subdivide this group of 37 even further, by looking at the eight quarterbacks who (like Palmer) had a career year in terms of AY/A+ and returned to play the following season (note that Vinny Testaverde, John Elway, and Jim Plunkett also had their best AY/A+ seasons when they over 35 but did not get significant playing time the following year; Elway and Plunkett retired, and Testaverde missed virtually all of 1999 with an injury).

This group did better than the population as a whole (average AY/A+ of 128.4) but also saw a steeper decline the following season (average AY/A+ of 92.9, meaning they actually played at a below league-average level).

Except for Doug Flutie (who declined by 25 units or about 1.7 standard deviations), this group all declined by at least two standard deviations. Only Randall Cunningham (in 1999) and Steve DeBerg (1991) played at an above league-average level.

Player Year Age Tm Year
Att 		Year
AY/A+ 		Y+1
Att 		Y+1
AY/A+ 		AY/A+
Diff
Randall Cunningham 1998 35 MIN 425 136 200 104 -32
Steve DeBerg 1990 36 KAN 444 132 434 101 -31
Dave Krieg 1994 36 DET 212 132 521 93 -39
Y.A. Tittle 1963 37 NYG 367 131 281 73 -58
John Brodie 1970 35 SFO 378 126 387 98 -28
Rich Gannon 2002 37 OAK 618 126 225 90 -36
Charley Johnson 1974 36 DEN 244 125 142 90 -35
Doug Flutie 2000 38 BUF 231 119 521 94 -25
AVERAGE 128.4 92.9 -35.5
MEDIAN 128.5 93.5 -33.5


None of this is to suggest Palmer cannot play at a high level going forward. The Cardinals' offense remains loaded with talent and is led by Bruce Arians -- widely considered one of the league's better coaches -- and Palmer himself has been an above-average quarterback for most of his career.

It does seem, however, that history is not on his side.