It isn't just the fact that the team made no effort to bring back free agent Knowshon Moreno, but the team has just three very unproven running backs on the roster behind Ball.
Ronnie Hillman and C.J. Anderson combined for just 256 yards rushing on 62 attempts last season. Hillman was also benched due to his issues hanging onto the football.
Behind them is Jerodis Williams, who has yet to carry the ball in a regular-season game and will be a long shot to make the team.
With the NFL draft less than one month away, the Broncos should be preparing to select at least one running back to add depth.
Lucky for them, there is an excellent choice this year that shouldn't cost them any more than a pick in the third round of the upcoming draft.
Ka'Deem Carey could be slipping down draft boards after running just a 4.70 40-yard dash at the NFL Scouting Combine, though he was able to improve that a tad at his own pro day. Teams could shy away from Carey due to his lack of elite speed.
While he may not be as fast as Chris Johnson, there is plenty of upside to the former Pac-12 standout.
Running Between the Tackles
Carey is not the biggest running back (5'9", 207 pounds), but he runs with a purpose.
He hits the hole with a nice burst and fights for extra yards, usually taking tacklers with him. He has very good vision and above-average balance.
Very similar to Maurice Jones-Drew, Carey will follow his blocks and take on defenders to move the chains. He is very rarely brought down by the first tackler.
While Carey does not have breakaway speed, he can be very productive if he hits the second level of the defense.
He has a beautiful jump cut that can spring him for big gains, and while he won't outrun anyone, Carey will almost always pick up yards after contact.
He finished second in the nation with 1,885 yards on the ground last season.
Catching the Ball
Carey can be a very useful weapon in the passing game as well, something that is a must in the Denver offense.
He has great hands and can turn a screen pass into a huge gain or run out as a wide receiver (check the 1:42 mark of above video for an example of this) to give his quarterback another option.
In his career at Arizona, he caught 77 passes, four of which went for touchdowns.
He is also willing to aid in pass protection and, with the right coaching, could become very effective in that area, too.
Where Would Ka'Deem Carey Fit in Denver?
Is this starting to sound familiar? Moreno gave the Broncos essentially the same things, and while he wasn't the quickest running back in the NFL, he still had over 1,000 yards rushing and 60 receptions on the season.
As a rookie, Carey could come in and pick up where Moreno left off, challenging Hillman and Anderson for the No. 2 slot on the depth chart. If nothing else, he could push Hillman to be the player Denver hoped it was getting when they selected him in the third round of the 2011 draft.
What will be Denver's plan if Ball goes down to injury? The Broncos need a player like Carey to help them stay balanced on offense.
If teams around the league base their entire evaluation of Carey on his 40-yard dash, they are going to miss out on what will be a very productive NFL player.
Denver can't make that mistake. They will draft a running back in May, and John Elway should have a keen interest in Carey. If he is there in the third round, he needs to pull the trigger.