With spring practice beginning next week, HuskerOnline.com begins our in-depth look at each position with our 2020 spring position previews.

Today we start things off by analyzing the running backs heading into spring practice.

Previous position previews: QB

There is one proven commodity in Nebraska's running back room right now, and that's senior Dedrick Mills.

After joining the Huskers as a junior college transfer last season, Mills emerged as the No. 1 back by the end of the year and led the team with 745 rushing yards and 10 touchdowns.

Even more, his 143 carries were nearly 100 more than the next running back on the roster. Now-departed Maurice Washington was second with 50, and the next highest returning total this season is redshirt freshman Rahmir Johnson at 21.

Redshirt freshman Ronald Thompkins is also back, but there are still questions about his long-term future after a series of significant injuries and surgeries.

That means that Nebraska's backfield is going to be as sparse as we've seen in some time when it comes to established experience and production. It also doesn't help that new important additions - true freshmen Marvin Scott III and Sevion Morrison - won't join the mix until the fall.

Walk-ons Brody Belt - who played in all 12 games last season and rushed five times for 32 yards - and Zach Weinmaster could get plenty of work this spring as well.

In all, four of NU's five scholarship running backs this season will be true or redshirt freshmen.

Nebraska will also likely utilize spring ball to work on other aspects of its running game with the quarterbacks and receivers.

Quarterback Adrian Martinez (who will be limited this spring) was NU's second-leading rusher last season with 626 yards and seven scores on a team-high 144 attempts. In fact, three of the Huskers' top-five returning rushers from 2019 are quarterbacks.

Receiver Wan'Dale Robinson was third on the team with 88 carries for 340 yards and three touchdowns, but head coach Scott Frost has said he wants to scale back the sophomore's workload as a running back going forward.

While there are about as many pressing questions facing Nebraska's running backs as any position on the roster, one of the biggest is what the future holds for Thompkins?

This is a player that, when healthy, would be a huge asset to the Huskers' backfield this season. However, injuries have prevented him from even really joining the conversation thus far.

Thompkins was one of the best running back prospects in the country going into his junior year at Loganville (Ga.) Grayson, but a right ACL injury ended his season. Then, in the first game of his senior year, he tore his left ACL.

Still, the former three-star stayed with Nebraska over 18 other offers from the likes of Alabama, Auburn, Florida, Florida State, Georgia, Indiana, LSU, Oregon, Penn State, and USC.

But there's now building concern about when or even if Thompkins will be able to reach his lofty potential. He needed another cleanup surgery last season after suffering a setback, and he'll be limited at best this spring.

The Huskers will continue to hold out hope that Thompkins can get back to 100 percent, but that is far from a certainty at this point.

Given that Nebraska is only going to have two fully healthy scholarship running backs entering the spring, the opportunities are going to be boundless for a guy like Johnson.

He got some chances to play last year while still maintaining his redshirt eligibility, but this is going to be an important spring for him to solidify himself as the clear No. 2 going into the start of fall camp.

The dynamic of the running back competition is going to change in a big way upon the arrivals of Scott and Morrison, so anything Johnson can do to elevate his stock now will be big for his role in 2020.

It will be the same case for Belt, who earned some playing time as a redshirt freshman walk-on last year and got nice praise from his coaches.

But Johnson probably won't have this this kind of golden opportunity to make his mark again, and he needs to capitalize on it.

1 - Dedrick Mills, Sr.

2 - Rahmir Johnson, RFr.

3 - Ronald Thompkins, RFr.

-OR-

Brody Belt, So.

4. Zach Weinmaster, RFr.