Is 2015 a Career-Defining Year for Carson Palmer in the NFL?

The NFL's best story is waiting to be told. It's out there, in the desert, languishing in the twilight of a 35-year-old journeyman quarterback's career.

Six years removed from his last playoff appearance and 10 years removed from the only season he posted a passer rating over 100, he just finished rehabbing yet another ACL rupture on the least talked-about NFL team, per Emory Sports Marketing Analytics' social-media equity study.

Carson Palmer is an unremarkable veteran on his third team in 11 seasons. His record as a starter is 70-73. He's a forgettably competent guy who, in Arizona, has made more headlines for being unable to play than anything he's accomplished on the field.

One great season from Palmer could recast him as a legend.

You see, Carson Palmer was once a Chosen One. He was a Heisman Trophy winner and a No. 1 overall pick.

In his second season as a starter, he led the league in completion percentage and touchdown rate. That year, he led the Cincinnati Bengals to the playoffs—he led the Cincinnati Bengals to the playoffs—and made his first of two consecutive Pro Bowl appearances. He signed a massive contract that added six years to the end of his original six-year rookie contract, locking him up through 2014 at a potential cost of over $118 million.

Palmer was a franchise quarterback, a blue-chip prospect who put up better numbers faster than Peyton Manning, Andrew Luck or nearly anyone else in NFL history:

Rk	Name	Cmp%	Yds	TD	Int	Rate ▾	ANY/A	Y/G
1	Russell Wilson	63.42	9950	72	26	98.6	6.93	207.3
2	Dan Marino	61.04	11431	98	44	96.4	7.53	265.8
3	Jeff Garcia	62.22	10360	74	33	91.5	6.63	230.2
4	Carson Palmer	63.79	10768	78	43	91.5	6.41	239.3
T-8	Ben Roethlisberger	62.4	8519	52	43	87.9	6.19	207.8
T-8	Joe Flacco	62.01	10206	60	34	87.9	5.96	212.6
13	Andrew Luck	58.58	12957	86	43	86.6	6.33	269.9
14	Cam Newton	59.8	11299	64	42	86.4	6.2	235.4
17	Peyton Manning	60.39	12287	85	58	85.4	6.35	256

Here's where the stories of the two Carson Palmers diverge.

Less than two weeks after signing that extension, Palmer made his first playoff start. As he let fly his first postseason pass attempt—a 66-yard bomb to the late Chris Henry—Pittsburgh Steelers lineman Kimo Von Oelhoffen rolled up on Palmer's leg. Ligaments shredded, cartilage tore and a kneecap was displaced.

Palmer, incredibly, answered the bell for the following season opener, started all 16 games for the Bengals and made his second straight Pro Bowl. His stats took an understandable step back from 2005, but he still played very well. Nobody feared the presumptive future Hall of Famer falling apart.

Then, in 2007, he led the NFL in interceptions. In 2008, a damaged elbow ligament ended his season. He refused Tommy John surgery, opting for rest and rehab. In 2009 and 2010, Palmer looked profoundly mediocre; his deep game was missing, and his passer rating hovered in the low 80s.

Marcio Jose Sanchez/Associated Press

Palmer and the Bengals mutually soured on each other. Oakland Raiders head coach Hue Jackson traded a first- and second-round pick to obtain the disgruntled California boy, and signed him to another big extension—but things didn't go well there either.

Arizona Cardinals head coach Bruce Arians needed just a conditional seventh-round pick and a swap of late-round picks to pry Palmer away from Oakland. For the third time, he was to be the savior of one of the NFL's most wayward franchises. For the second time, he was.

The NFL's collective consciousness misses this fact, because 2013 Carson Palmer didn't look any different than the 2007-12 editions. The Cardinals' incredible turnaround was driven by the defense; Palmer's mere professional competence was enough to allow the Birds to snag 10 wins out of the NFL's toughest division.

With a full season in Arians' complex offense, Palmer looked stronger in 2014 and so did the defense. After 10 games, the 9-1 Cardinals sat atop the NFL and looked set to own the No. 1 seed and home-field advantage in the stronger of the two conferences.

Rick Scuteri/Associated Press

Having finally found their quarterback and the wayward Chosen One finally having found a home, Palmer and the Cardinals agreed to a three-year, $50 extension in the middle of the season. That was Friday, November 7. On Sunday, November 9, Palmer blew out his left ACL again. Without his services, the Cardinals floundered to an 11-5 finish and lost to the Carolina Panthers in the first round of the playoffs.

Now, how do we tell his story?

The classic three-act structure relies on two "turning points," dramatic crises that define the three major sections of the tale. If we use the Von Oelhoffen play and the for-peanuts trade to the Cardinals as the two major turning points of Palmer's career, look at the tale the stats tell:

Years	GS	Cmp%	TD%	Int%	Y/A	Rate	ANY/A	Sk%
2004-06	45	63.8	5.3	2.9	7.4	91.5	6.41	5.2
2007-12	76	61.8	4.2	3.3	7.1	83.2	5.8	4.4
2013-14	22	63.2	4.4	3.1	7.4	87.2	6.06	5.9

His touchdown rate, interception rate, average yards per attempt, passer rating and adjusted net yards per attempt all declined after his first three seasons on the field and improved over the last two. 

Palmer's 2014 season was really, really good—one of his best ever. His 4.9 percent touchdown rate was his best since before his first knee injury, and his 1.3 percent interception rate was by far the lowest of his career. His passer rating (95.6 percent) and adjusted net yards per attempt (7.09) were both second only to his 2005 season. In 2014, the two different Carsons merged back into one man.

Jamie Squire/Getty Images

Had he stayed healthy, it's likely Palmer would have led the Cardinals deep into the postseason, maybe even all the way to the Super Bowl. This is the ending the narrative demanded: his place in the world found, his setbacks overcome and his apparent lifelong destiny fulfilled.

His injury didn't just cost the Cardinals their best chance to win a championship since Kurt Warner's late-career renaissance brought them millimeters short of winning Super Bowl XLIII. It cost Palmer his chance to repeat Warner's career-defining redemption.

His astonishing out-of-nowhere appearance at the very top of the NFL in 1999, and that incredible playoff run a decade later, bridged a much longer period of wandering in the metaphorical desert than many remember. Warner's middle period, from his 2001 Super Bowl defeat at the hands of Tom Brady to his earning the Cardinals starting job, wasn't just mediocre, it was bad:

Years	GS	Cmp%	TD%	Int%	Y/A	Rate	ANY/A	Sk%
1999-01	43	67.2	7.0	3.8	9.06	103.4	7.87	5.9
2002-06	31	63.9	2.4	2.7	7.19	82.1	5.38	8.5
2007-09	42	65.4	5.3	2.9	7.52	93.6	6.68	4.3

Warner's redemption period didn't exude jaw-dropping greatness, either, but three good seasons paired with a stunning wild-card run to the Super Bowl re-wrote his entire career. With that moment of glory, Warner went from a flash-in-the-pan trivia answer to a serious Hall of Fame candidate, as Football Outsiders' Scott Kacsmar discussed.

If Palmer plays a complete 2015 season at his 2014 levels, he has a chance to enter the elite club of 40,000-yard, 250-touchdown passers. At this moment in history, it has only 13 members: Seven are Hall of Famers, and four are mortal locks (Manning, Brady, Drew Brees and Brett Favre).

Early reports out of minicamp indicate Palmer has picked up right where he left off.

"There’s nothing changed about him," star Cardinals wide receiver Larry Fitzgerald told ESPN.com's Josh Weinfuss. "He throws a great, accurate ball. He’s made a lot of plays throughout this minicamp already, and we’re looking forward to many more during training camp."

If Palmer proves this summer that mental rust isn't an issue, he should be set to take on history this fall.

Should Palmer, like Warner, bring postseason glory to the desert, joining that elite statistical club in the process, his story will instantly be rewritten—from barely remembered has-been to a hallowed legend whose tale is told for ages.