The 49ers have been known as an offensive team ever since Bill Walsh came over from Stanford in 1979. Since that time, the 49ers have been known to score points, especially for fantasy football. With Hall of Famers Joe Montana, Steve Young, and Jerry Rice, the Niners have always had offensive superstars. Kyle Shanahan was hired in 2017 to continue that tradition, but things have not worked out as well as most thought.
Sorting out the Shanahan Running Back Shuffle
Shanny is seen as an offensive guru. One of the trademarks of a Shanahan offense is a zone running scheme. The scheme is meant to allow shifty running backs to pick their spot, and use spacing along the offensive front to find running lanes.
Shanahan mastered this with Devonta Freeman and Tevin Coleman in Atlanta. With offensive success, comes fantasy football success. The Falcons had many players that helped win fantasy championships in 2016, including these two top-20 RB’s. Devonta Freeman would finish as the RB6, with Tevin Coleman the RB19. Together they had 1,599 yards on 345 attempts and scored 24 total touchdowns.
What really stands out is how much both backs were used in the passing game. Between Coleman and Freeman, they had 883 receiving yards on 85 receptions on 105 targets. Shanahan likes to use his back in passing situations, and this strategy helped him land the head coaching job in San Francisco.
San Francisco Treat
Looking at the last five years, play-calling patterns have emerged. Using Eli Grabanski’s play-calling tendencies charts, we can see the evolution of Kyle Shanahan’s play-calling when it comes to running the football. Seven out of thirteen years, Shanahan gave 50 percent of more carries to his team’s lead back. Since 2018 however, Shanahan has spread the wealth.
Now, many factors have led to this evolution. Shanahan may have felt that he didn’t have a lead ball carrier the last three seasons, so he went with a ‘hot hand’ approach. Shanahan may have also felt that switching up runners gives an advantage to the offense due to play-calling tendencies being reversed. Whatever Shanahan’s reasoning, one thing is clear; in the last three years he has split carries amongst his RBs.
From 2018-2020, no back has seen more than 160 carries under Shanahan. No lead back has seen more than 41 percent of carries, either. What can be considered a cluttered backfield in San Fran has held water. In 2021, this will be no different.
Trey Sermon to the Rescue?
Many folks believe that San Fran has found their true do-everything back in Trey Sermon. The Niners traded up to land Sermon in the 2021 NFL Draft. With Matt Breida and Tevin Coleman heading out of town, Raheem Mostert being 29 years old, and a collection of journeymen in Jeff Wilson Jr, Wayne Gallman, and Jamycal Hasty being part of the backfield, Sermon seems to have every opportunity to take over lead duties.
Then the Niners threw a wrench into the lead runner plan. In the 6th round of the 2021 NFL Draft, the Niners took Elijah Mitchell out of Louisiana. Many teams had a higher grade on Mitchell than the 6th round, and looking at his RAS scores he has a stellar athletic profile. He ran a lighting fast 4.32 forty, and there were times he looked electric at Louisiana. So what does this pick say about the 49ers backfield? Let’s dig in.
The Splits
Some will see this as the best player available move, but looking at the trends, the Mitchell pick signifies what the data has shown. Shanahan will use both Sermon and Mitchell this year, and look to build on their skillsets in the next 2-3 years. I also foresee another RB joining the group in 2022.
As of this writing, Jeff Wilson is set to miss the first two months of the season after tearing his meniscus in OTA’s. That leaves Mostert, Gallman, Sermon, Mitchell, and Hasty still contending for snaps. One of these guys will not make the final 53-man roster unless another injury happens. I could also foresee Mostert being a cap casualty if Mitchell impresses. That would leave four RB’s vying for carries in 2021.
Looking at the splits that last two years, the breakdown has been:
| 2019 | Carries | Percent | Games |
| Mostert | 137 | 32% | 16 |
| Coleman | 137 | 32% | 14 |
| Breida | 123 | 29% | 13 |
| Juszczyk | 3 | <1% | 12 |
| Wilson | 27 | 6% | 10 |
| Total | 427 | 100% |
| 2020 | Carries | Percentage | Games |
| Wilson | 126 | 32% | 11 |
| McKinnon | 81 | 21% | 16 |
| Mostert | 104 | 26% | 8 |
| Juszczyk | 17 | 4% | 16 |
| Hasty | 39 | 10% | 8 |
| Coleman | 28 | 7% | 8 |
| Total | 395 | 100% |
Based on this breakdown, below is a projection of what the RB splits should look like in a full 17-game season.
| 2021 | Carries | Percentage | Yards |
| Mostert | 140 | 33% | 630 |
| Sermon | 130 | 30% | 585 |
| Gallman | 80 | 19% | 360 |
| Mitchell | 60 | 14% | 270 |
| Juszczyk | 20 | 4% | 90 |
| Total | 430 | 100% | 1935 |
Using a breakdown of what Shanny has done in the past, we can take a look at what a likely split will be in 2021 and beyond. I used a healthy 4.5 per carry average to determine the projected yards. This has been a slight tick above what RBs have averaged the last five years of Kyle Shanahan calling plays. My contention is that Shanahan likes to split carries; he has taken a New England approach to his running game. Shanny likes to feel out his guys and use them differently in each given circumstance.
Perhaps Shanahan is a victim of the injury bug, and that could be a reason he varies the carries of his backs; and that he does so out of caution rather than preference. But it ends up being clear – Shanahan likes to split carries not only throughout the season, but throughout games.
Another interesting fact is that no RB in the last two years has received more than 22 carries in a single game. In fact, in the last 32 games, there have only been three instances where one RB carried the ball more than 20 times. There have been 10 times when two or more backs have received double-digit carries.
Shanahan either believes he doesn’t have a back that can carry the load, or he likes to spread things around. Either way, these trends are headed for a similar split in 2021.
Target Shares
The San Francisco running backs are not only split in the run game, but their passing game targets are split as well. Going back to his Atlanta days, it is clear that Shanahan likes to use his backs as pass-catchers. The following is a percentage breakdown of the target share among his RB group since 2016. The great FB, Kyle Juszczyk is used in this analysis as well because as long as he’s in San Fran he will get touches. Keep that in mind with Sermon as well.
| Year | Targets | RB Target Share | Total Pass Attempts |
| 2016 | 115 | 21% | 537 |
| 2017 | 166 | 27% | 607 |
| 2018 | 107 | 20% | 532 |
| 2019 | 103 | 27% | 476 |
| 2020 | 137 | 24% | 570 |
Shanahan has averaged a 24% RB target share over the past five seasons. I’ve applied this to the 2021 RB room based on the historical breakdown of how Shanny uses his RBs. The expected outlook is broken down below.
| Player | Targets | Target Percentage | Yards |
| Mostert | 31 | 30% | 217 |
| Sermon | 26 | 25% | 182 |
| Gallman | 29 | 28% | 203 |
| Mitchell | 10 | 10% | 70 |
| Wilson | 7 | 7% | 49 |
While I have continuously seen Trey Sermon’s fantasy football ADP fall (from 122 to 111 in SuperFlex (SF) Redraft and 97 to 92 in SuperFlex Dynasty), Raheem Mostert’s ADP has jumped slightly.Mostert has gone from 92 to 94 in SF Redraft and 118 to 120 SF Dynasty.
The splits are clear. Whether it’s Mostert, Gallman, Mitchell, or Wilson when healthy; Shanahan is going to split carries, which will devalue Trey Sermon as his career moves forward.
There is this belief that San Fran’s running game is elite, and are players you want to own for fantasy football. That belief is largely due to the Falcon’s success in 2016 and the 49er’s success in 2019, but the data paints a different picture.
| Year | Rush Yards | Rank | Rush Yards/Att | Rank |
| 2016 | 1928 | 5 | 4.6 | 4 |
| 2017 | 1664 | 21 | 4.1 | 17 |
| 2018 | 1902 | 13 | 4.5 | 15 |
| 2019 | 2305 | 2 | 4.6 | 10 |
| 2020 | 1889 | 15 | 4.3 | 18 |
Other than 2016 and 2019, Shanahan’s run game has been mostly average. I hear the Shanahan offense narrative that any back can thrive. There have been flashes from Mostert, Wilson, and Tevin Coleman the last few years, but the 49ers are not the Ravens. They are an average rushing offense that will have a middling QB, or a rookie QB starting.
The data paints a clear fade. This is a situation in all formats that I will be avoiding until I see Shanahan start to use more of a lead-back system. Until then, I will assume he will split carries. Even when the 49ers traded up for Trey Sermon, they still chose to pick Elijah Mitchell in the 6th round. They like a lot of backs in their stable and the data spells that out.
Rookie Fever
In rookie drafts, this is a weak RB class from top to bottom. Harris, Etienne, and Javonte Williams are all solid pieces, but there isn’t a Saquon Barkley or Ezekiel Elliott; and many of the rookies landed in bad situations.
I still rank Sermon as my fantasy football RB4 in this year’s rookie class, but unless you can land Sermon in the 8th round or later in dynasty startups (or in your redraft leagues), I am fading the 49ers backfield situation. Trust the data, play the odds. Look elsewhere unless the value is so overwhelming you are forced to take Mostert or Sermon.
This will again be a frustrating fantasy football year for owners of the 49ers backfield. It’s becoming a perennial headache, much like Belichick’s backs in New England have been for 15 years. Get over the rookie hype, trust the trends, and look for other players of value around the 8th round. This is how you win. The San Francisco backs have not been a San Francisco treat to fantasy football owners, and I feel this will continue in 2021 and beyond.
