Have these 11 NFL stars peaked, or is the best yet to come?

Brady believes he can be a very good 40-year-old QB (1:33)

Five-time Super Bowl champion Tom Brady says he's got a lot left in him and wants to play into his mid-40s. (1:33)

The peak of a player's career can come at any time. We naturally assume players will post their best numbers in their late 20s, and while that is the case for most players, it's hardly the case for everyone. Wide receiver Anquan Boldin's most productive seasons were his first and third years in the league, and he's still plugging away with the Buffalo Bills as he enters his 15th season. "Peaking," in other words, doesn't necessarily mean a player will have a disappointing career from that point forward.

In advance of 2017, though, I thought it might be interesting to look at some notable players from around the league and try to gain a sense of whether we've already seen their most impressive seasons. This isn't to suggest that any of them are washed up or that they aren't at their best; in the cases where history suggested players have peaked, most of the time we're arguing that the context in which that player topped out will be difficult to reproduce.

I'll mention one or more key statistics for each player and project whether they'll top that number again, either in 2017 or later in their career.

Let's start with the most legendary active player in the league.

Tom Brady, QB, New England Patriots

Tom Brady missed four games with a suspension last year and will turn 40 in August, but he continues to defy the effects of aging. Brady produced the best adjusted net yards per attempt (ANY/A) of his career since 2007 last season. By the era-adjusted pro-football-reference.com stat ANY/A+, Brady had the best age-39 season in league history last year. He also welcomes Brandin Cooks to town this year, alongside a returning Rob Gronkowski. The New England Patriots are stacked on offense.

There are a couple of hurdles in Brady's way. One is that the path for quarterbacks after 40 is basically uncharted. There is exactly one quarterback since the merger to start 10 or more games during his age-40 season: Brett Favre, for the 2009 Vikings. He was effective, posting a 123 ANY/A+ (100 is league-average), but Favre was done a year later. Warren Moon and Vinny Testaverde were right around league average at age 41, and Moon even started 10 games at 42, but we're looking at a three-quarterback sample in nearly 50 years. Quarterbacks -- even great ones like Favre and Peyton Manning -- lose it with little warning at the end of their careers.

The other problem is that Brady's been so incredible in the past that it would require something truly special to top his 2007 or 2010 seasons. Brady should be the best 40-year-old quarterback in league history, but the idea of him getting better in his forties is hard to imagine. He's still the favorite for MVP, but Brady has peaked.

Marshawn Lynch, RB, Oakland Raiders

Brady's fellow Northern Californian makes his return to the NFL this year, as Lynch came out of retirement after one season and left the Pacific Northwest to head home. Lynch takes over the starting job for the Oakland Raiders from departed free agent Latavius Murray, and he'll be playing behind the league's best offensive line. It's entirely possible that Lynch's year off has served to refresh the five-time Pro Bowler, and at 31, it's totally reasonable to think he has plenty left in the tank.

It's also fair to wonder if Lynch was already on the way down before his retirement. He struggled mightily during his final year in Seattle, averaging just 3.8 yards per carry before missing the second half of the season due to injury. That was behind a dismal offensive line, but Thomas Rawls averaged 5.6 yards per carry and posted a better DVOA and success rate behind most of the same linemen.

There's also the simple reality of usage. Lynch averaged nearly 299 carries during his three-year peak with the Seahawks between 2012 and 2014, and Seattle was a different sort of football team. A simple measure of a team's style I like to use is their run/pass split on first-and-10 while the game is within 14 points. From 2012 to 2014, the Seahawks ran the ball 60.4 percent of the time in those situations, which was the second-highest rate in football. Last year, Oakland ran the ball 49.2 percent of the time in those spots, which was 21st in the league. They replaced offensive coordinator Bill Musgrave with quarterbacks coach Todd Downing, but given the fact that the Raiders just gave their starting quarterback $125 million, it's hard to believe this will be Lynch's team as opposed to Derek Carr's. Lynch could be a useful player in his return, but it's unlikely he'll ever top the 1,590 rushing yards he racked up during the 2012 campaign.

Greg Olsen, TE, Carolina Panthers

The Carolina Panthers tight end is in the news, thanks to the public suggestions he might choose to hold out for a new deal this season. The reports of unease among veterans like Olsen and Thomas Davis has been suggested as a cause for the firing of Panthers general manager Dave Gettleman, although Davis says such a claim is unfair.

It's fair to say Olsen has been underpaid, although not by an enormous amount. The Panthers ripped up the extension Olsen signed after being traded from Chicago with three years to go and gave the Miami product a new deal with $21.3 million due in its first three years. That was the league's third-biggest tight end contract when it was signed, and its eighth-largest now, although Olsen's 2017 cap hit is second in the league among tight ends. Since arriving in Carolina, Olsen hasn't missed a game and ranks third in receiving yards (5,384) among tight ends, behind Jimmy Graham and Rob Gronkowski.

The problem with a new Olsen deal is that the idea is to pay a player for what he's going to do, not what he has done. Olsen turned 32 in March, and while he has rolled off three consecutive 1,000-yard seasons, tight ends in their age-32 season or older have delivered a grand total of one 1,000-yard season, courtesy of a 32-year-old Tony Gonzalez in 2008. The rising tide of the NFL's passing game makes Olsen a plausible second case, and he should still be productive in the years to come, but it's hard to believe Olsen will ever top the 1,104 receiving yards he amassed in 2015.

Michael Bennett, DE, Seattle Seahawks

One of the rare Seahawks to earn a new contract with two years remaining on his previous deal, Bennett confirmed his future would be in Seattle by signing a three-year, $30 million extension in December. It's not an enormous deal -- Bennett's extension ranked 18th in three-year value among edge rushers when it was signed, given that the bulk of the new money kicks in from 2018 and beyond.

The 31-year-old Bennett has been more disruptive than his sack numbers would indicate; he perennially ranks among the league leaders in hits when healthy, but he hasn't been able to turn that into a mammoth sack campaign. During his four years in Seattle, he has racked up 94 quarterback knockdowns. The typical player turns 43 percent of his hits into sacks, which would suggest Bennett should have recorded just more than 40 sacks during his time with the club.

Instead, Bennett has racked up 30 sacks during the past four years. That's nothing to be ashamed of, but given that the hit-generated baseline for Bennett has been 10 sacks per season and Bennett hasn't yet topped that 10-sack total, there's reason to believe Bennett hasn't yet peaked.

Julio Jones, WR, Atlanta Falcons

Julio Jones' production dropped off by 462 yards between 2015 and 2016, but it was still a banner year for the Falcons star. He missed two games, but he averaged 100 receiving yards per game for the fourth consecutive season and still racked up 1,409 receiving yards during Atlanta's remarkable 11-win campaign. Jones then chipped in with 334 receiving yards and three touchdowns during the playoffs. We're an offensive line penalty away from remembering his ridiculous catch as the defining moment of the Super Bowl.

The Alabama product may very well top his 2016 production this year, especially if he can make it through all 16 games. Can he hit the lofty heights of 2015, when he racked up 1,871 receiving yards? That will be tough, if only because everything has to go right for a receiver to rack up that many yards.

During that season, Jones stayed on the field for 16 games, just the second time in his career that has occurred. The Falcons had an offensive coordinator in Kyle Shanahan who loved to focus on his No. 1 receiver, which led to a career-high 203 targets. Jones became just the fifth receiver since 1992 to rack up more than 200 targets in a season, and nobody has ever had more than one 200-target campaign. Atlanta didn't really have a No. 2 wideout, with a badly decayed Roddy White serving in the role.

The 2015 Falcons were also a mediocre team that got into all kinds of shootouts. Atlanta ran 1,073 plays, which was sixth in the league, with Matt Ryan and Sean Renfroe attempting 621 total passes, the eighth-most in football. With the Falcons improving dramatically and running out the clock during the second half last year, they threw the ball only 537 times, the seventh-fewest pass attempts in the NFL. It seems weird, but the Falcons might be too good for Jones to challenge his 2015 peak anytime soon.

Le'Veon Bell, RB, Pittsburgh Steelers

If anybody deserves to be paid like two players, it might be Le'veon Bell. The Steelers back reportedly turned down a contract extension from Pittsburgh because he felt like he deserved to be paid as both a No. 1 running back and a No. 2 wide receiver combined. Given that Bell came within 146 yards of becoming the third back in league history to post 1,000 rushing yards and 1,000 receiving yards in the same season back in 2014, he's as versatile as any skill-position player in football.

There are two issues keeping Bell from an MVP-caliber season. One is the presence of Antonio Brown, as the brilliant wide receiver demands a bevy of targets in his own right. The other is staying on the field. Injuries and suspensions have prevented Bell from completing a single full season from Week 1 through the postseason as a pro. He has missed 20 of the 70 games Pittsburgh has played since he entered the league in 2013.

Strangely, that may actually be a strong argument that we haven't seen Bell's best. It's tough to predict that Bell will stay on the field for all 16 games in any individual season, but chances are that he'll eventually piece together at least one season in which he's active and available the entire way. It also appears plausible that Bell will leave Pittsburgh as early as next season, and whichever team acquires Bell is likely to give their new star running back an even larger workload. The 2,215 yards from scrimmage Bell racked up in 2015 is the 22nd-largest mark in league history, but I suspect he'll top it at least once before he hangs up his cleats.

Andrew Luck, QB, Indianapolis Colts

Only the most optimistic Colts fans are rosy about Luck's 2017 season. Luck's January shoulder surgery initially had a six-month recovery time frame, but we're now in August, and concerns about Luck's availability for training camp have now stretched to Week 1 of the NFL season. If Luck is going to top his previous highs, it doesn't seem like he'll be doing so during a 2017 season that might top out at 14 games.

Luck's best NFL season was his 2014 campaign, when he threw for 4,761 yards and a league-high 40 touchdowns while leading the Colts to the AFC Championship Game. Will the Stanford product, who turns 28 next month, be able to top those season-long bests at any point in the remainder of his career?

Yes and no. I suspect Luck with a good offensive line might be able to leap over that yardage total, given that the 2014 season was also the one in which Luck enjoyed the lowest sack rate (4.2 percent) and pressure rate (24.3 percent), respectively, of his career. Those Colts had a dismal running game thanks to the presence of Trent Richardson, who averaged 3.3 yards per carry while Indy's backups averaged 4.5 yards per rush. But as teams continue to get more pass-friendly, it's not crazy to imagine Luck approaching or eclipsing 5,000 yards in a season.

What might be more difficult, though, is jumping past 40 passing touchdowns in a single year, which is still the 11th-highest total in league history. Teams are throwing more near the goal line, but offenses still ran the ball 55 percent of the time inside the 5-yard line last year. Offenses converted nearly 40 percent of their carries into touchdowns, but the Colts were down at 22.2 percent, the fourth-worst rate in the league. With a better back -- and it will be hard to find a starter worse than Richardson -- Luck won't need to throw 40 touchdowns.

Cam Newton, QB, Carolina Panthers

A lot has changed in a year for the 2015 MVP, as both the Panthers and their franchise quarterback struggled mightily last season. The seemingly unbreakable Newton took a beating early in the year before missing a game with a concussion. Newton slumped to his worst passer rating as a pro, and he narrowly missed the worst ANY/A of his career by one one-hundredth of a yard, with a 5.46 ANY/A that would actually qualify as his worst if you compare it with the rising passing performances around the league.

Newton was also far less productive as a runner, racking up just 359 yards on the ground after averaging 641 rushing yards per year during his first five seasons in the league. I suspect that's a change that could stick around. The Panthers have publicly suggested that they want to take some of the rushing workload off of Newton, a move that led them to use their top two picks in this year's draft on hybrid weapons Christian McCaffrey and Curtis Samuel. Newton should have better protection in the future, making it less likely he'll need to scramble out of the pocket to make plays. And running quarterbacks like Randall Cunningham, Fran Tarkenton and Michael Vick had each peaked in terms of rushing yardage by the time they turned 27. Newton's entering his age-28 season.

As a passer, though, Newton could very well top his previous high in terms of yardage, which was actually the 4,051 yards he racked up as a rookie in 2011. If the Panthers' plan to take some of the pressure off of Newton is effective, his receivers may help Newton reach those new heights. Since he entered the league in 2011, Newton's average pass has traveled 9.5 yards in the air, second in the NFL behind Jameis Winston. With shorter passes to the likes of McCaffrey and Samuel, Newton should be able to push up his completion percentage and rack up steadier chunks of yardage.

Ezekiel Elliott, RB, Dallas Cowboys

Elliott struggled in the first two weeks of the 2016 season before running roughshod over opposing defenses. From Dallas' third game on through its 15th, Elliott averaged 115.2 rushing yards per game before sitting out their meaningless Week 17 encounter. The Ohio State star followed it up with 125 yards in Dallas' postseason loss to the Packers.

It's hard to think of the last rookie running back who was as effective as Zeke, but let's present him anonymously in table form:

Pretty similar, no? Player B is Alfred Morris, currently Dallas' third-string back. Morris racked up huge numbers as a rookie in Washington, but his rushing yardage total has dropped in each of the four ensuing seasons, bottoming out with 243 yards behind Elliott last season.

Maybe it's not fair to compare Elliott to Morris, who looked like a star during that one year Washington turned Robert Griffin III and the zone-read offense into the league's most terrifying offensive attack. Elliott's a top-five pick and Morris was a sixth-round afterthought. You would argue that Morris was in the best possible situation for a running back to succeed, but wouldn't that also be the case for Elliott in 2016?

The Cowboys had the best offensive line in the NFC, with three Pro Bowlers in the prime of their careers combining to miss a total of just two meaningful games. The other two starters were veterans with years of experience in Dallas, both of whom (Doug Free and Ronald Leary) are now gone. It's hard to imagine the Cowboys fielding an offensive line better than the one that was in front of Elliott last year, given that even great offensive lines have a shelf life of a few seasons at most.

Elliott was also playing in an offense that was basically designed to feed him carries. The Cowboys got a stunning level of play from rookie quarterback Dak Prescott, but as Prescott matures, it would hardly be a surprise to see Dallas ask him to throw more than the 456 passes he threw last year. The Cowboys were also without star receiver Dez Bryant for a chunk of last season, and Bryant would have demanded the ball on a more frequent basis had he been in the lineup.

The Cowboys also won 13 games, which meant that they were running the clock out in the fourth quarter in lieu of throwing the ball, which they'll have to do more if they're trailing. Elliott ended up with 322 carries last year, which is a huge outlier in the modern NFL. Elliott was the only back in football to top the 300-carry mark, although Le'Veon Bell averaged more attempts per game (21.8) than Elliott (21.5).

Put it this way: There have been 36 backs since the merger to produce a single season with 1,600 rushing yards or more. Just 12 of those backs have repeated the feat. It's tempting to separate those into two groups, with one-offs like Morris in one and perennial superstars like LaDainian Tomlinson in the other, but there are plenty of true franchise backs who weren't able to get to those lofty heights again. Top-five picks like Edgerrin James, George Rogers, Jamal Lewis, and even Tony Dorsett got more than 1,600 yards once -- and never again.

It's a real feat to be as good as Elliott was in 2016, combining both his natural talent and an optimal set of surroundings. Elliott surely won't be able to top his 1,631 yards again in 2017, given that it appears likely he'll be suspended for as many as six games, but the odds are also against him getting past that mark again as a pro.

Rob Gronkowski, TE, New England Patriots

Gronk has always been a ticking time bomb, thanks to the physical nature of his game and the back injury that cost him his final year at Arizona. The back flared up again last year and eventually led to season-ending surgery, although the Patriots won the Super Bowl without their star tight end.

The four-time Pro Bowler already holds the record for most receiving yards (1,327) and receiving touchdowns (17) by a tight end in a season, marks he set during his breakout season of 2011. Given that Gronkowski appears to be healthy after undergoing surgery, could he set even higher marks for a Patriots team that appears set to roll over the world in 2017?

I would be skeptical. But as with Elliott, it has nothing to do with Gronkowski's ability; 2011 was also the last time Gronkowski played a 16-game season, and while he could stay healthy for an entire campaign, the Patriots have been incredibly cautious in trying to keep Gronkowski out of harm's way. They've sat him throughout the entire preseason for years and took him off of special teams since Gronk broke his forearm blocking for an extra point in 2012. If the Patriots clinch the top seed in the conference and/or have nothing to play for late in the season, Gronkowski is almost definitely going to sit. That alone reduces his chances of racking up huge totals in the counting stats.

In addition to the perennial injury concerns surrounding the Patriots star, there are simply too many weapons to go around in New England these days. Gronkowski will get his targets in the red zone, sure, but can he really expect to grab the 130-plus targets he'll need to approach those receiving totals on a team with Brandin Cooks, Julian Edelman, Chris Hogan, James White and Dion Lewis all expecting regular receptions?

At the same time, I'd worry about counting out a player who has set the bar on what we think tight ends are capable of accomplishing in the NFL. Gronkowski hasn't topped those 2011 totals, but he remains a historic outlier in terms of touchdown rate. Maybe the Patriots turn him into a player who plays only on the opposition's side of the field, and a fresh Gronkowski racks up 20 touchdowns. It's easier to believe that Gronk will pull off something totally unexpected and unprecedented than it is for just about anybody in the league, even if it's not necessarily likely to happen in 2017.

Vic Beasley Jr., DE, Atlanta Falcons

Let's finish up with the league's sack leader from 2016. Beasley was one of the few bright spots for the Falcons' defense before it caught fire during the postseason, as he racked up an NFL-high 15½ sacks. Beasley forced six fumbles, which tied him for the league lead with Bruce Irvin, mainly by stripping the ball out of quarterbacks' hands as he came around the edge. For a guy who was being written off as a bust after a frustrating, injury-riddled 2015 and a proposed move to outside linebacker, the former eighth overall pick accomplished a considerable amount during his sophomore campaign.

Will there be an even more promising followup? It's unlikely. For one, as I mentioned with Elliott, the vast majority of players who make it to lofty heights don't end up getting there again. There have been 65 players to generate 15 or more sacks in a season since the league made sacks an official statistic. Forty-seven of those guys -- more than 72 percent -- failed to do it a second time. Great pass-rushers like Jason Taylor, Warren Sapp and Robert Mathis finished their careers with one campaign of 15-plus sacks. Guys like Robert Quinn and Jason Pierre-Paul were brilliant early in their career and haven't generated that sort of output since.

The other issue with Beasley is that his 15½ sacks came with a total of just 16 quarterback knockdowns, which is usually a strong indicator of sacks on their own. For reference, the NFL has (reasonably) reliable hit data since 2006, and the other players to rack up 15 or more sacks averaged more than 29 knockdowns.

Typically, a player will turn about 43 percent of his hits into sacks, which would peg Beasley's 16 hits to generate just under seven sacks. Players who outperformed their sack totals by that much in years past have often declined, and while Beasley may exhibit some consistent ability to force fumbles, he'll need to hit the quarterback more frequently to generate lofty sack totals. Chances are that we've already seen his best season.