SANTA CLARA, Calif. -- On one side of the field Sunday, the Carolina Panthers' offense leans heavily on speedy, do-everything running back Christian McCaffrey.

On the other side, the San Francisco 49ers' offense relies heavily on speedy, do-everything running back Matt Breida. Or Tevin Coleman. Or Raheem Mostert. Or Jeff Wilson Jr.

The Panthers and Niners represent two of the NFL's nine best rushing attacks. Unlike Carolina, where McCaffrey has thrust himself into the middle of early MVP conversations, the 49ers are punishing teams with one of the league's most productive running back stables.

How the Niners have used their quartet has added up to one of the most productive and relentless rushing games in the NFL. Entering Sunday's game against the Panthers, San Francisco is second in the league with 172.7 rushing yards per game, yards before contact (117.2 per game) and rushing first downs (8.9) per game and fourth in yards after contact (55.5 per game). The Niners also lead the league in rushing attempts per game at 39.

In the long line of success that coach Kyle Shanahan, run game coordinator Mike McDaniel and running backs coach Bobby Turner have brought from their previous stops, this version of their run game might be their deepest yet, even if it drives fantasy football owners up the wall.

"That's [Shanahan's] offense," Mostert said. "When he was in Atlanta with Tevin and [Devonta] Freeman, they were a 1-2 punch and now I can see us as being a 1-2-3-4 punch. It's one of those things where we've got to keep each other at a certain level and our mentality is, 'Hey, if I'm gonna eat, I know my brother is gonna eat, too.' It's not too, 'Oh, I'm the starter, this, that and the other.' We're all gonna get our fair share and when we do, we have just got to make the most out of them."

In most running back committees, there are usually two things that are true.

First, those teams rarely invested big money or draft capital in the position, instead believing that good backs can be found via multiple means. Second, those teams have often gone in search of running backs who complement one another, with the idea that one's weakness might be another's strength.

These 49ers have flipped that idea on its head. Since Shanahan and general manager John Lynch arrived in 2017, San Francisco has made adding running back talent a priority. That talent has come through the draft (Joe Williams), rookie free agency (Breida and Wilson), veteran free agency (Jerick McKinnon and Coleman) and even trade (the short-lived stay of Kapri Bibbs).

While some might see the offseason addition of the speedy Coleman as superfluous, Shanahan and the Niners saw it as a chance to add another talented player at a position where they'd been hit hard by injury in 2018.

"To me, you just try to get the best guys available in every aspect and then you try to use their traits accordingly, whatever gives them the best chance to be successful," Shanahan said. "We've tried to do that."

That approach left the Niners with a stable of speed burners who could compete as a high-quality 4x100-meter relay team. Shanahan said that wasn't necessarily the idea, but it's no coincidence that all of the Niners backs are capable of playing on any down in any situation.

"Our guys are similar in the fact that they all can run," Shanahan said. "Jeff probably being the slowest one out of those guys, but that's just because he doesn't run 4.3. They all have a little bit different styles and the same with receivers and things like that. But, you always try to get the best possible and then just use it however you need to."

The Niners' 234 rushing attempts are the most through a team's first six games since the New York Giants in 1993, according to ESPN Stats & Information.

Therein lies the key to keeping everyone happy.

"Once you are working for something bigger than yourself and have common goals, it makes it easier for you," Wilson said. "Obviously, all of us want to touch the ball the most and obviously that's not going to happen, so it's about us knowing our roles and knowing our position and just playing our role so we can get this Super Bowl trophy. If that's none of us getting a touch, one of us, two, three, four, however we've got to do it, we do it."

While that approach might be a radical departure to what McCaffrey is doing in Carolina, it's also proved quite effective. Breida leads the team with 411 rushing yards -- which ranks just 13th in the NFL among running backs -- but Mostert (249) and Coleman (227) rank 34th and 40th in the league, respectively. No other team has more than two running backs in the top 40.

What's more, Breida (5.63) and Mostert (5.53) rank third and sixth, respectively, in yards per carry. And with those two consistently breaking off big gains, Coleman and Wilson have emerged as best-equipped to handle the dirty work. That pair has accounted for six of the team's seven rushing touchdowns and converted six of the team's 11 third-and-1 conversions.

Aside from Coleman's sprained ankle in the opener against Tampa Bay, the Niners' backs have been able to stay healthy and fresh. That's been a welcome sight after Breida and Mostert were hampered by injuries last season.

"It takes a lot off your body throughout the season," Breida said. "You don't have to worry about getting beat up throughout the season. That's why I think we're all pretty much healthy right now."

Through it all, the Niners' running back quartet has formed a unique bond free from jealousy or frustration over touches. The group keeps an ongoing text message thread that also includes fullback Kyle Juszczyk and McKinnon and can be seen in games cheering on one another until it's time to sub in.

"We all complement each other so well and we all bring a lot of similarities to the game plan," Mostert said. "It's a long season. We've just got to make sure that we're staying healthy and they're doing a great job rotating us. That's just how all of us are. We go in and we're real effective."