Often such years come as a significant surprise, as was the case in 2020 when Justin Jefferson broke the record for receiving yards by a rookie, topping 1,400 having only posted 70 through his opening two games.
But frequently it is possible to project breakout seasons before they happen by looking at the numbers from previous years and the situation a player finds himself in heading into the campaign.
Using its advanced metrics, Stats Perform looks at five players poised to emerge with stellar performances in the 2021 season.
Joe Burrow – Cincinnati Bengals
The fate of the Bengals' season, and perhaps that of head coach Zac Taylor, rests predominantly on how Burrow fares on his return to regular-season action after a serious knee ligament injury curtailed his rookie year.
Burrow, the first overall pick in 2020, being back at his best is far from a guarantee. However, the former LSU star has seemingly grown in confidence in the preseason after some initial struggles in training camp and demonstrated enough in his 10 games last campaign to suggest he can justify his draft status and lift the Bengals from the AFC North cellar.
The primary issue facing Burrow is the lack of talent on the offensive line protecting him, which is a lowly 28th in the NFL per Stats Perform's rankings, with Cincinnati bemusing many by selecting wide receiver Ja'Marr Chase instead of tackle Penei Sewell with the fifth pick in this year's draft.
Yet Burrow does an excellent job of moving in the pocket and finding lanes out of it to escape pressure. He reads the field well and delivers his throws with consistently accurate placement. Burrow ranked sixth in the NFL among quarterbacks with at least 100 pass attempts with a well-thrown percentage of 80.6.
That number dipped to 69.8 when under pressure, but still gave him the best mark of any quarterback in the AFC North, reflecting his poise when the pocket breaks down.
With Chase joining Tee Higgins and Tyler Boyd in an impressive wide receiver room, Burrow has the weapons to make a huge leap in year two providing he stays healthy and the offensive line can produce even a slight improvement.
Damien Harris – New England Patriots
While the New England offense disappointed for the most part last year, their running game was efficient, and Harris played a significant role.
He averaged five yards a carry in recording 691 rushing yards and two touchdowns in 10 games. Those latter two numbers may be slightly underwhelming, yet Harris was one of the premier backs in the league when it came to getting to the second level of the defense in a hurry.
A patient back who reads his blocks intelligently, Harris' decisiveness and burst when he identified the running lane to hit allowed him to average 3.11 yards before contact by a defender per attempt, putting him 10th in the NFL.
His rate of 2.05 yards after contact was less impressive but still above the average of 1.91, while Harris was 11th in the NFL with 3.15 yards per carry on rush attempts where there was a run disruption by a defender.
The Patriots possess the third-best run-blocking line in the NFL, according to Stats Perform's rankings, and – though Cam Newton's exit may make their ground game less diverse – Harris could reap the benefits of facing lighter boxes if Mac Jones' impressive preseason translates into the regular season and gives New England's passing attack a much-needed jump.
Brandon Aiyuk – San Francisco 49ers
The 49ers' second first-round pick of 2020 was in a difficult situation as he dealt with sub-par quarterback play between the struggles of the oft-injured Jimmy Garoppolo and backup Nick Mullens before they finished the season with C.J. Beathard.
However, the former Arizona State receiver still excelled in defeating coverage with his route-running ability and showed his potential with the ball in his hands after the catch.
Aiyuk caught 60 passes for 748 yards and five touchdowns in 12 games as a rookie. He added a further two scores on the ground.
His big-play percentage of 33.1 was third among rookies with at least 50 targets behind Gabriel Davis and Tee Higgins. Davis has Stefon Diggs, Cole Beasley and Emmanuel Sanders as competition for targets with the Buffalo Bills while Higgins will have to share the receiving workload with Chase and Boyd.
George Kittle and Deebo Samuel will command a significant number of targets for San Francisco but Aiyuk holds an undisputed position at the top of the wide receiver depth chart, meaning he will likely see enough passes thrown his way in 2021 for him to outperform both Davis and Higgins.
With Garoppolo healthy and Trey Lance lurking as a high-upside successor, Aiyuk is in a much better spot in 2021 to surpass 1,000 yards and establish himself as one of the league's brightest young stars at the receiver position.
Marcus Davenport – New Orleans Saints
Davenport has yet to justify the trade up the Saints struck to draft him in 2018 despite flashes of the brilliance that convinced New Orleans to make such a dramatic move up the board.
His influence was limited by a series of injury issues in 2020 but Davenport still registered a pressure rate of 21.3 per cent that was 11th among edge rushers. His run disruption rate of 15.7 per cent was 12th.
The Saints did spend a first-round pick on an edge rusher in Payton Turner, whose stock rose dramatically late in the process. However, with Trey Hendrickson, who had 13.5 sacks last year, having departed for a lucrative payday with the Bengals, Davenport is in line for a clear uptick on the 374 defensive snaps he played in 2020.
At his best, Davenport is an explosive pass rusher blessed with tremendous power who can drive blockers back with the bull rush but also bend around the edge and flatten to the quarterback with excellent closing speed.
The Saints have not seen his best often enough, yet if he can stay healthy, Davenport can play a crucial role for the New Orleans defense as part of a front that has enough talent to ensure he will regularly have the benefit of one-on-one matchups to help him significantly pad his career total of 12 sacks.
Darious Williams – Los Angeles Rams
There is a strong argument that Williams has already enjoyed his breakout campaign, having racked up 14 passes deflected and four interceptions for the Rams last year.
Despite his superb 2020, Williams is not a player talked about as one of the premier cornerbacks in the NFL. Should he back up last season's efforts with a similarly productive 2021 for a Rams team many expect to contend for the Super Bowl following Matthew Stafford's arrival, that may change.
Williams excels at reading the eyes of the quarterback to break on the football and make plays at the catch point, with his ball skills reflected by his gaudy press breakup and interception numbers.
Only K'Waun Williams of the San Francisco 49ers allowed a burn, which is when a receiver wins his matchup with a defender on plays where he is targeted regardless of whether the ball is catchable, at a lower rate than Williams, who did so on 30.3 per cent of balls thrown in his direction.
Williams' big-play percentage allowed of 16 was the 12th-best among all cornerbacks and, though his on-ball production may be a product of playing across from Jalen Ramsey, the fact he so frequently stood up to the test when challenged by opposing passing games indicates he is a player who can continue his ascent in his fourth year.
