The stats aren't good when it comes to Detroit's rushing attack in 2016. The Lions ranked 30th in yards per game (81.9), 25th in average per rush (3.8) and 25th in negative runs (48).

The foot injury suffered by starting running back Ameer Abdullah Week 2 that ended his season certainly didn't help matters, but there are some that think the Lions need to add another potent rusher to pair with Abdullah, Theo Riddick, Zach Zenner and others.

"I'm always looking to upgrade," Lions GM Bob Quinn said after the season when asked if he thought Abdullah and Riddick can be productive players in Detroit's backfield moving forward.

"That's what my job is, I think the players understand that. I think the number of new players that we brought in this year and the number of guys we tried out and worked out, I think it was eye opening to a lot of people.

"My eyes are always open. If we can get somebody better, then great. But do I believe in Ameer and Theo and Zach (Zenner) and Dwayne Washington and Mike James? I do."

Quinn could be in a position at pick No. 21 to select one of the draft's elite running backs.

With the NFL Scouting Combine fast approaching, here's a look at some of the running backs to keep an eye on during the week in Indianapolis:

DALVIN COOK

School: Florida State

Ht/Wt: 5-11, 213

Best trait: He's a rare runner that can take it to the house every time he touches the ball. He was sixth in rushing in 2015 with 1,691 yards and ranked fifth this past season with 1,765 yards. He scored 19 touchdowns in 2016. He has great vision and can cut on a dime.

Concern: Fumbles (12 in three years) have been an issue. He's also had shoulder surgeries and some off-the-field issues. He's not a particularly tough runner between the tackles. He's much better in space than he is hitting a gap, putting his head down and getting tough yards.

The skinny: He's a homerun hitter (10 career runs of 50-plus yards) with a great burst. He could be a nice complement to Abdullah and Riddick in Detroit's backfield if the other concerns get checked off.

LEONARD FOURNETTE

School: LSU

Ht/Wt: 6-1, 235

Best trait: He's built like a brick house with receiver speed. Fournette led the SEC in all-purpose yards as a true freshman (137.4 per game). That's a pretty tough feat in that conference. He followed that up with 1,953 yards and 22 touchdowns as a sophomore. He runs with great power, but can also run away from defenders.

Concern: He struggled with a bad ankle most of this past season and finished with 843 yards, though his 120.4 yards per game and 6.5 average still led the team. His game is all about power, which could open him up to injury concerns at this level. He's not real shifty. He sees it, hits and tries to run over whoever is in his way.

The skinny: Fournette has a rare blend of size, speed and power. He's a power back with great speed, which makes him a big-play threat and a nightmare to tackle in the second and third levels.

CHRISTIAN MCCAFFREY

School: Stanford

Ht/Wt: 6-0, 197

Best trait: He does it all. He set a NCAA record with 3,864 all-purpose yards in 2015, ranking second in the FBS with 2,019 rushing yards, along with 645 receiving and 1,070 kickoff return yards. He won the Paul Hornung Award as the nation's most versatile player that year. Despite being hampered by injury this past season, McCaffrey still rushed for 1,639 yards.

Concern: He logged more than 300 touches in each of the last two seasons at Stanford. He also won't break a lot of tackles. He's more shifty than he is a tough runner.

The skinny: He doesn't overwhelm anybody with his size, speed or power, but his production is off the charts. He's elusive and just finds ways to make plays. Great football I.Q. The fact that he can also be a return man gives teams lots of options with him.

ALVIN KAMARA

School: Tennessee

Ht/Wt: 5-10, 215

Best trait: There's not a lot of tread on Kamara's tires. After bouncing around from Alabama to community college and then finally settling in at Tennessee, he carried the ball just 107 and 103 times the last two seasons, but still averaged 6.5 and 5.8 yards per carry, respectively. Had 23 touchdowns in just 284 touches at Tennessee. He has good speed and wiggle for a player his size.

Concern: Combine medicals will be important for Kamara as he has had knee injuries in his past. Can he be a bell cow for a running game? That's unproven at this point.

The skinny: Kamara has some traits that teams will like. If his medicals check out and he tests well at the Combine, teams will find a place for a talented runner with a lot of upside, who can also be a return man.

D'ONTA FOREMAN

School: Texas

Ht/Wt: 6-1, 249

Best trait: Foreman was a consensus All-American and Doak Walker Award winner after leading the FBS with 184.4 rushing yards per game this past season. He finished with 2,028 yards on 323 carries with 15 touchdowns. He's a north-south runner, but has good lateral movement for a back his size.

Concern: He lost six fumbles this past season. The quickest way to lose the trust of an NFL coach is to put the ball on the ground.

The skinny: He's probably not going to give teams much on third down, at least initially, but he's a very productive big back for teams looking for their thunder to pair with lightning.