The San Francisco 49ers probably only anticipated one contract drama this offseason, but they were likely not expecting a trade request from running back Raheem Mostert. That has now posed the question: just how valuable is the hero of last season's NFC Championship game to the franchise?
It is not an easy question to answer.
Mostert's impact for the 49ers down the stretch and in the playoffs was remarkable and worthy of the pay raise he is seeking from San Francisco, but it's difficult to praise him without attaching the significant caveat of his success coming in an offensive system that has churned out productive running backs with startling consistency.
Since 49ers head coach Kyle Shanahan first became a coordinator with the Houston Texans in 2008, he has overseen 1,000-yard seasons for Steve Slaton, Alfred Morris and Devonta Freeman. Morris (2012 & 2013) and Freeman (2015 & 2016) each reached the four-figure mark in successive seasons while Carlos Hyde came within 62 yards of 1,000 yards in Shanahan's first season in charge of the Niners.
Morris, Freeman and Hyde have all compiled respectable NFL careers, but the list of 1,000-yard backs under Shanahan is not exactly a who's who of elite players at the position, lending credence to the notion that Mostert's production could be easily replaced.
Though history says the 49ers should continue to excel running the ball regardless of who is in the backfield, the numbers suggest Mostert's efficiency may be tough to replicate.
Mostert's open-field excellence
Mostert's 772 rushing yards in the regular season came at a league-leading yards per carry average of 6.5 and by almost every Football Outsiders measure he was a top-10 back in the NFL last year.
He ranked seventh Defense-adjusted yards above replacement (DYAR), which measures a running back's overall value and ninth in Success Rate, which gauges their consistency.
In Defense-adjusted value over average (DVOA), which measures per-play value, Mostert ranked first. To put it in other words, no running back in the league was more valuable on a per-play basis than Mostert.
Much of Mostert's value came in what he was able to do at the second level and in the open field. The 49ers ranked eighth in Football Outsiders' Adjusted Line Yards, which assigns rushing yardage to the offensive line. However, they were also seventh in the league in Second Level Yards and third in Open Field Yards, indicating that – while the offensive line played a pivotal role in San Francisco's ground game dominance – the running backs were similarly influential in maximizing the impact of the rushing attack with what they did once they got to the second level.
No running back did more at the second level and beyond than Mostert, whose consistency in ripping off significant gains owed much to his easy track star speed and hugely impressive elusiveness, which saw him regularly evade defenders in the open field and deliver game-changing plays.
The 49ers' running back room is a crowded one, but do they have a player capable of potentially filling the void in terms of producing in such an efficient manner by eluding defenders in the open field, or is there a free agent back who could step in and perform to the same standard?
Coleman boasts the speed and change-of-direction ability to thrive in the open field, and he did so at times during his first season with the 49ers in 2019, most notably in a four-touchdown showing against the Carolina Panthers.
There was little consistency to Coleman's play last year, though, and that was reflected by his performance in the Success Rate metric, in which he ranked 44th.
With Coleman finishing a lowly 41st in DYAR and 43rd in DVOA, it is tough to argue that Mostert does not deserve to be paid at least at the same level as a player to whom he was vastly superior in 2019.
Wilson has made his name with the 49ers as a goal-line hammer and the player who caught the game-winning touchdown in San Francisco's win over the Arizona Cardinals at Levi's Stadium last season.
However, he has much more to his game than just sheer thump. Wilson lacks the initial burst through the hole and the speed of Mostert and Coleman, but his agility is intriguing while his DVOA performance hints at a player who could prosper in an expanded role.
Wilson earned a DVOA rating of 20.3% on his 27 rushes in 2019. Mostert's league-leading number for players with a minimum of 100 rushes was 26.8%.
Even in the event of a Mostert departure, the odds of Wilson becoming a focal point of the offense look slim, yet there is evidence he is worthy of greater run in Shanahan's committee backfield.
Having restructured the lucrative contract he signed in 2018 after an ACL tear cost him two seasons, it is difficult to know what to expect from McKinnon. If he is anywhere close to his best, McKinnon will be a valuable addition to the backfield as he has the speed and fluid movement to serve as another dynamic open-field threat for the 49ers.
The 2017 season was the high watermark for McKinnon as he recorded 991 scrimmage yards but his metrics from that campaign, which saw him finish 40th in DYAR and DVOA and 28th in Success Rate, indicate he would struggle to match the influence of Mostert.
Shanahan is unlikely to have designs on using him in the same way as Mostert. McKinnon was signed largely for his abilities as a receiver and, if he can rediscover his 2017 form after two years away, it will be him running the kind of routes his absence forced Wilson and others to run last year. The 49ers hope he will do so with a much more devastating impact.
McKinnon is not a Mostert replacement but, if all goes to plan, he will be a high-octane complement.
In a normal year, undrafted free agent Hasty stepping into Mostert's shoes right off the bat as a rookie may have been a possibility.
Whether he'll have the time in the Niners' abbreviated preparations for the 2020 campaign to make a big enough impression to contend for a roster spot is unclear, but there is much about Hasty's skillset to excite.
An extremely effective receiver out of the backfield, Hasty demonstrated tremendous burst through the running lane in his time at Baylor, while the proclivity he has displayed for making defenders miss in tight spaces should allow him do the same in the open field with a level of success akin to that of Mostert.
Hasty might not be trusted to take on a key role in the offense right away but, if he sticks on the roster or the practice squad, he has the attributes to quickly ascend to a point where he is an integral part of the running game.
Ahmed is the back on the 49ers' roster whose running style is most comparable to that of Mostert. He doesn't have the same burst but he's a quick-twitch athlete whose acceleration through the gears looks smooth and easy.
Swiftly changing direction is no problem for Ahmed, whose touchdown run on fourth down for Washington in the Huskies' 2019 season opener with Cal served as evidence of what he can do in the open field.
With the shortened offseason, Ahmed at this stage looks destined to lose out in the numbers game given the depth the 49ers have at the position. However, the Niners have identified two undrafted free agent backs who fit the scheme excellently and have the traits to enjoy early success if their number is called.
Devonta Freeman, a free-agent fill-in?
In the event that the 49ers and Mostert are not able to come to an understanding and they part ways, one free-agent running back stands out as an obvious replacement.
Freeman remains on the open market following the end of his time in Atlanta and the prospect of pairing him with Coleman in the Shanahan offense once again would be an enticing one.
He has not been the same player since Shanahan left the Falcons for the 49ers, but at 28 there should still be gas in the tank for a back who when at his best in 2016 showcased a penchant for sending defenders to the ground with intelligent use of his foot quickness.
His elusiveness was reflected by the Falcons finishing seventh in Second Level Yards and third in Open Field Yards in 2016, matching what the Niners did in 2019.
Yet for all Freeman's success under Shanahan, his numbers in individual metrics from 2016 were inferior to those of Mostert from last season. Freeman was 13th in DYAR, 14th in DVOA and 12th in Success Rate, with then 49er Hyde among those to outperform him in DYAR and DVOA.
What can be gleaned from comparing Mostert with his backfield mates and a free agent who is a natural fit in the Shanahan system is that, while the Niners would probably succeed in harnessing the production they require from the likes of Coleman, McKinnon and Wilson or by bringing in Freeman, that production is unlikely to be as efficient or as consistent.
Hasty and Ahmed are the unknowns and, in a season as unique as the 2020 campaign, the risk in giving either of them the opportunity to fill the void a Mostert exit would leave outweighs the reward.
Shanahan and general manager John Lynch may not see giving a pay rise to a running back as a wise investment. Though the history of Shanahan's offense and specifically the rushing attack supports that line of thinking, an analysis of the advanced metrics suggests there is value in keeping around a player who has maximized the potential of the Niners' ground game and making him feel properly compensated.
The 49ers appear to have recognized this, with NFL Network's Ian Rapoport reporting a high-ranking member of the organization met with Mostert to "clear the air."
Whether that leads to a resolution over his contract remains to be seen, but Mostert's ability to reproduce his second-half dominance in 2019 over a full season could be pivotal for the Niners offense in 2020. With Mostert under contract through 2021, the 49ers hold all the leverage and could theoretically just ignore his request, yet keeping Mostert in the right mindset by satisfying his financial demands is a step worth taking to make sure San Francisco's offense is at its most potent in the coming campaign.
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