The Trey Lance discussion has been an impossible one to escape during the NFL's long offseason.

That is largely because the circumstances in which he takes his first steps as a starter are unprecedented.

Lance was selected by the 49ers with the third overall pick in last year's draft after they traded three first-round selections for the right to move into that slot.

After a rookie year largely spent watching on the sideline, he now steps in to start at the most important position for a team who were minutes away from reaching a second Super Bowl in three years last season, which ended in heart-breaking defeat to the Los Angeles Rams in the NFC Championship Game.

Young quarterbacks have taken over Super Bowl-calibre teams in years gone by. Aaron Rodgers took over from Brett Favre in 2008 after the Green Bay Packers had agonisingly lost the NFC Championship Game to the New York Giants in overtime.

But Rodgers had spent three years as Favre's backup in an era where spending an apprenticeship on the bench was de rigueur for highly drafted quarterbacks, and he had previously produced two seasons of stellar play for a Power 5 school during his college career with the Cal Bears.

Lance, by contrast, played just one full season of college ball at North Dakota State in the FCS – college football's second tier – back in 2019, losing the chance to add to his experience as the coronavirus pandemic wiped out his 2020 campaign with the Bison, save for one exhibition that essentially served as a pre-draft audition for the dual-threat signal-caller.

A quarterback of such little experience being given the keys to one of the best teams in the NFL is an objectively fascinating situation, one made even more intriguing by the Niners' decision to hang on to Jimmy Garoppolo, his predecessor, after failing to find a partner for a potential trade.

Rodgers did not have Favre looming as the backup in Green Bay. Favre retired, then came back, but was traded to the New York Jets, leaving Rodgers to plot his path to becoming one of the all-time greats.

Lance will be tasked with keeping a win-now team firmly in contention for a Super Bowl title while dealing with the possibility of the man who twice helped the 49ers to the cusp of the Lombardi Trophy stepping in should he struggle.

The flashes Lance produced in his two starts in relief of an injured Garoppolo last season were promising, but with the 49ers set to kick off their new era against the Chicago Bears on Sunday, can he immediately rise to the challenge of leading the NFL's most interesting team on a deep playoff run they hope will end with a sixth league championship? 

An ideal offensive ecosystem

In order to answer that question, it is important to look at just how strong Lance's supporting cast is.

Head coach Kyle Shanahan and general manager John Lynch have put together one of the most complete rosters in the NFL having taken over a team in need of a colossal rebuild in 2017.

Shanahan himself is a key reason for confidence the transition to Lance will work. No play-caller in the NFL does a better job of consistently putting his receivers in space and his quarterback in favourable situations, while his diverse running torments opposing defenses year in, year out.

The league's pre-eminent play-caller also has experience of building an offense around a dual-threat quarterback, having done so while working as offensive coordinator for the Washington Commanders under his father Mike as Robert Griffin III produced an Offensive Rookie of the Year campaign.

Shanahan's play-calling acumen is a critical factor in the 49ers' ceaseless efficiency on offense. The 49ers' offense finished last season ranked first in Stats Perform's Efficiency Versus Expected (EVE) metric. EVE looks at down, distance, yards from goal, quarter, time remaining and score difference. Using those six factors, Stats Perform trained a model to predict yardage output for any game situation. From there, the projected yards are compared to the actual yards gained or prevented in those situations.

But San Francisco's superiority in that metric would not be possible without a star-studded cast of offensive skill-position players, which Stats Perform AI ranks as the sixth-best in the NFL coming into the year.

Between Deebo Samuel, whose ability to excel as a dual wide receiver-running back inspired the Niners' turnaround from a 3-5 team to one who came within a whisker of an eighth Super Bowl appearance, fellow wideout Brandon Aiyuk and All-Pro tight end George Kittle, Lance is not short of targets who will make his life much easier.

A run game that ranked eighth in explosive runs of 10 yards or more in 2021 with 58 – a tally Lance's presence will surely embellish – will also provide him with plenty of assistance, as will a defense that has a compelling case for being considered the league's gold standard.

Stellar defensive support

The 49ers' Divisional Round win over the Green Bay Packers last season perhaps provided the clearest evidence yet as to the value of their outstanding defense.

San Francisco shackled back-to-back MVP Rodgers, limiting Green Bay to one touchdown and field goal in an improbable 13-10 road win against the number one seed in the snow at Lambeau Field.

Defensive coordinator DeMeco Ryans called a masterful game as the 49ers' defensive front sacked Rodgers five times, and it is the seemingly endless supply of depth on the defensive line that makes Ryans' group arguably the league's most fearsome.

The 49ers led the league in pass rush win rate and did so while blitzing at the fifth-lowest rate in the NFL (20.4 per cent). That D-line now heads into 2022 arguably in an even stronger position. Nick Bosa, coming off a 15.5-sack season, leads an edge rusher rotation that is six players deep and includes a rookie, in second-round pick Drake Jackson, whose pressure rate of 24.2 per cent was fifth among draft prospects at his position last year. 

On the interior, the 49ers are hoping former first-round pick Javon Kinlaw, with his hulking 6ft 5in, 319-pound frame, can put it all together in his third season following knee surgery and form an imposing tandem with Arik Armstead, whose 2021 stunt-adjusted pass rush win rate of 44.34 per cent was fifth among defensive tackles (min. 100 matchups).

Behind the D-line, the coverage versatility of a linebacker core headlined by the game's best in Fred Warner opens a wealth of options for Ryans, yet it may be the additions in the secondary that solidify his defense as the league's elite this season.

The 49ers are starting a fifth-round rookie at nickel corner. That is a frightening sentence on the surface, but Samuel Womack III allowed a burn rate – which measures how often a receiver wins his matchup with a defender on a play where he is targeted – of just 33.3 per cent in his final year with Toledo. That was tied for the best among draftable corners. He backed up those numbers with a preseason that saw him record two interceptions.

While the 49ers are hoping Womack's leap to the highest level is seamless, it is the performance of free-agent signing Charvarius 'Mooney' Ward that could determine the ceiling of this defense. Ward's burn rate of 39.8 per cent was the fourth-best among corners with at least 50 targets last year, with the former Kansas City Chief fifth in burn yards per target (7.96).

The acquisitions of Ward and Womack have significantly strengthened the cornerback room. Though there is justified concern about a lack of depth at safety, Ward's arrival may facilitate the 49ers leaning more on the man coverage in which he specialises, enabling San Francisco to blitz up front more often and perhaps even improve their pressure numbers from a year ago.

Regardless of whether the pressure statistics do get even better, it is clear Lance is entering an outstanding ecosystem for a young quarterback. The 49ers have the talent to survive the ups and downs he may experience. The unknown is whether Lance can take advantage of his environment to help this team realise their glaringly obvious potential by enhancing an already excellent offense.

Becoming the 'because of' QB

Lance is a substantial departure from what the 49ers are used to at quarterback, and there are upsides and downsides to that change in direction.

There is no question Lance will significantly increase the 49ers' threat on deep passes. Last season, Garoppolo completed just nine passes of 21 air yards or more across the entire 2021 season. Lance completed four in his 10 full quarters of play as a rookie.

On top of that, Lance's air yards per attempt average of 10.1 was the second-highest in the NFL among quarterbacks with at least 50 pass attempts.

While the downfield passing game figures to be more explosive, Lance will need to improve in one area where Garoppolo has traditionally excelled.

Garoppolo has consistently done an impressive job of leading his receivers to the ball on throws over the middle, setting up regular opportunities for yardage after the catch.

Over the last three seasons, Garoppolo has averaged 6.7 yards after the catch (YAC) on his completed passes, almost a full yard more than his nearest challenger Patrick Mahomes (6.0).

The same sort of accuracy on throws where the receivers can relieve the burden on the quarterback with YAC was lacking from Lance during the preseason, and curbing a tendency to put those passes behind his intended target will be critical for him to realise his potential in Shanahan's vaunted offensive scheme.

But Shanahan is making a calculated trade-off in switching to Lance. The 'gimme' plays Garoppolo can hit with ease may not come as easy with Lance, but the 49ers will benefit from the 'second reaction' plays the new quarterback can make when the pocket breaks down.

Though Garoppolo can make throws on the move, the improvisation factor is significantly higher with Lance, who last season averaged a gaudy 13.06 air yards throwing on the run. 

On top of his threat as a downfield passer in such situations, Lance also put 8.45 yards per carry on scrambles in 2021. Only Jameis Winston (8.67) had more among quarterbacks with at least 10 scrambles.

Lance adds new dimensions to the 49er offense, but he also has shown substantial promise in a staple feature of the Shanahan attack.

Though it was on a small sample size, Lance displayed encouraging accuracy in the play-action game as a rookie. Ten of his 12 play-action throws were well-thrown, with Lance averaging 14.67 air yards on those attempts.

It is far too early to definitively say Lance will continue to be as accurate on play-action over the course of a full season. However, given the effectiveness of the 49er run game, the play-action should still continue to be extremely effective, with Lance's prowess on the ground giving defenders more to think about when he fakes the hand-off.

Former Los Angeles Rams, Buffalo Bills and Seattle Seahawks head coach Chuck Knox once said: "There are two kinds of quarterbacks. There is what I call the 'because of' quarterback and the 'with' quarterback. You win 'because of' Joe Montana or John Elway. You win 'with' Phil Simms or Doug Williams."

Garoppolo has produced game-winning performances for San Francisco, but while he has operated the offense extremely efficiently, he is firmly in the 'win with' category. In the biggest games where the team has asked him to put them over the top, he has not delivered.

The 49ers moved up for Lance due to their belief he can be a 'because of' quarterback. He may not perform with the same efficiency as Garoppolo, but he has already delivered showings to suggest he can be the decisive factor for a team who have come agonisingly close to glory. Lance's ability to reproduce those flashes over the course of an entire season will determine whether the 49ers were right in their assessment.