Age Before Potential in Detroit, Miami Backfields: Why David Montgomery and Raheem Mostert are Undervalued

Fantasy football is about value. Getting 100 total points from a guy you drafted in the 15th round is great; it’s a season-ruining bust from your first-round pick, though. You have an expectation based on the round in which you select each player.

That means evaluating players on the same team isn’t as easy as, “Who gets more yards?” Last season, I liked Brandon Aiyuk a lot more than Deebo Samuel Sr. because Aiyuk was being drafted several rounds later and the players had similar opportunities. That ended up being a good call when they finished the season very close in fantasy points.

I see two similar situations this season in NFL backfields. The Detroit Lions and Miami Dolphins each feature two fantasy-relevant running backs, one a veteran and the other a second-year player expected to take on a bigger role.

The newer backs are seen as much better fantasy options, and the reasoning makes sense: Younger players get better as older players get worse. These two teams were both highly successful last season, though, and have similar personnel. There isn’t reason for either team to make a major shift unless a player shows that he has significantly more or less talent than last season.

Let’s look at each team’s backfield situation and why I am higher on the veterans backs than popular projections. Players are listed with their rankings among running backs according to our ranks here at FantasySP. Point totals and rankings from past seasons are from FantasyPros.

Detroit Lions

Jahmyr Gibbs No. 4

David Montgomery No. 19 (21 in PPR)

Gibbs was the 12th overall pick in 2023 and entered the league with many expecting he would be the top guy in Detroit. Montgomery had signed a three-year, $18 million contract in free agency, but he was a middling player in Chicago.

Then Montgomery ran for 1,015 yards and 13 touchdowns while appearing in just 14 games. Gibbs had a strong year himself, rushing for 945 yards and 10 touchdowns, and he found a role as a receiver with 52 receptions on 71 targets for 316 yards and a touchdown.

Gibbs will be more acclimated to the NFL this season, but is there a reason to expect much else to be different? He will probably split rushes with Montgomery and work much more than the veteran in the pass game. Montgomery will probably get more short yardage/goal line work: Montgomery had 17 carries inside the 5-yard line in 2023, and Gibbs had 10.

Looking back to 2022, there was a similar dynamic with Jamaal Williams handling most of the running while D'Andre Swift was used more in the passing game. Williams’ 1,066 yards and 17 touchdowns aren’t far off from Montgomery’s 2023 numbers. Gibbs ran a lot more than Swift did, but this has been the system since before these current players came to Detroit.

Gibbs will be a very good fantasy player but expecting him to take a huge leap while minimizing Montgomery seems like it would go against the profile of this Detroit coaching staff and against what worked last season. This team had a 17-point lead in the NFC Championship Game; I can’t see them making any major changes on offense.

I don’t mean to demean Gibbs, though. This is more about my support for Montgomery, especially in standard leagues. Gibbs was 10th among running backs in both standard and PPR in 2023, while Montgomery was ninth in standard and 17th in PPR.

His draft status points to a borderline RB2/3 type; I see Montgomery as more of a top-20 near lock and possible top-10 guy if things break right.

Miami Dolphins

De'Von Achane No. 9 (10 PPR)

Raheem Mostert No. 25 (26 PPR)

This is a little different than the Detroit situation: I like Mostert more than his ranking, like Montgomery, but unlike Gibbs, I think this is too high for Achane. He entered the league as a possibly explosive player whose size could be an impediment to high usage/durability (he’s listed at 5’8, 188 pounds).

Achane’s rookie season was exactly that. He had a three-game stretch in late September/early October in which he had over 100 yards and averaged more than 10 yards per carry in each game, totaling seven touchdowns. Achane also appeared in just 11 games due to multiple injuries.

While the upside is drool-inducing, the injury risk may be just as high. Achane won’t keep up the same efficiency because nobody can; he was performing at historic levels. There will still be an explosive element, but anyone drafting Achane for his 2023 performance is going to be disappointed.

Other guys being drafted in the same area include James Cook, Isiah Pacheco, Travis Etienne and Derrick Henry. I’d rather have any of those players as my RB2 than Achane, who is closer to a flex option in my mind than a borderline RB1. Achane will likely have huge weeks again, but there is a good chance he will miss time.

Miami also likes to rotate backs, one of the reasons I’m more optimistic about Mostert. The 32-year-old had by far his best season in 2023, and it would be foolish to expect him to repeat that performance. Miami’s rushing attack is a machine, though, driven as much by the system as any individual greatness.

ESPN ranked the Dolphins 31st in pass blocking and eighth in run blocking, a big part of their success on the ground. Guard Robert Hunt signed a huge contract in Carolina, and his absence will make a difference. I also expect Miami to be able to replace their right guard in a successful rushing attack.

Mostert had 20 rushing attempts inside the 5-yard line while Achane was given just five. No other back had more than one attempt. Mostert is still listed at the top of the depth chart, and only fourth-round pick Jaylen Wright was added in the offseason.

Guys ranked near Mostert include Zack Moss, Tony Pollard, Jonathon Brooks and Devin Singletary; that’s not exactly the same level of talent that is being chosen near Achane. Oh, and I almost forgot: Mostert scored the second-most standard points and fifth-most PPR points among backs last season.

No, he probably won’t repeat that kind of performance in 2024, but Mostert is in position to handle a lot of rushing attempts for a really good offense, and he will likely get most of the goal line carries. Mostert feels more like a top-15 to 20 RB; I’m targeting him in all my mock drafts. The upside on Mostert is higher than the players being drafted around him.

Conclusion

While the younger back in both Detroit and Miami may end the season with more fantasy points than his veteran counterpart, I see the value leaning toward Montgomery and Mostert due to their pre-draft rankings in the mid-to-late rounds in fantasy drafts.

I love Gibbs as a fantasy back, and while I’m a little down on Achane, he is an explosive player who can be the top scorer any week. Targeting both Montgomery and Mostert later in drafts, though, may give you a near-weekly starter if one of these teams is able to re-create last year’s game plan and performance (easier said than done, I know).