ENGLEWOOD, Colo. -- At a time when the Denver Broncos have promised to run the ball more -- and even better than they did last season -- the competition for those carries will likely be the fiercest battle for playing time on the roster.

While some uncertainty arrives with any new coaching staff, the offense that coach Gary Kubiak runs has consistently churned out 1,000-yard rushers.

"Who is going to be the bell cow?" Kubiak asked earlier this week at the NFL's annual owners meeting in Phoenix. "Who is going to be a three-down player? They have to sort that out."

And sort it out they will since the Broncos have three players -- C.J. Anderson, Montee Ball and Ronnie Hillman -- who spent time as the team's lead back last season. Ball got the first chance in 2014 but had 55 carries before a groin injury sent him to injured reserve. Hillman was next before a foot injury sent him to the sidelines. Anderson closed out the year as a bit of a revelation with 648 rushing yards over the last six games of the regular season on the way to a team-leading 849 yards. Anderson showed vision, decisiveness and finishing power at the end of his runs, or exactly the traits Kubiak has said he wants in the offense.

But Anderson had not been the starter at the beginning of the season, or even the team's No. 2, because coaches thought he had shown up heavy for the team's offseason work last spring and looked sluggish. So much so, some with the team privately wondered if Anderson would hold on to his roster spot. Anderson was much quicker when the team returned for training camp last July, but by then Ball and Hillman were solidly No. 1 and No. 2 on the depth chart.

Kubiak has said Anderson enters the fray at the top of the depth chart. Anderson, who signed with the Broncos as an undrafted rookie in 2013, has some monetary incentive as well given he will be a restricted free agent at seaosn's end.

"He's a young player who got a big opportunity late last year at the end of the season and took advantage of it," Kubiak said. "You've seen when guys are going to make big jumps in this league that as great players, they usually make them in Years 1, 2 or 3, right in there. He made a big jump as a player and I think he's earned the right to walk into the offseason program or OTAs and line up as our starter, but it's something that he's got to continue to earn and continue to earn on a daily basis."

For his part Ball, who was the Broncos' second-round draft pick in 2013, vowed the day after the team's playoff loss to the Indianapolis Colts "to get back my job." Ball, too, was drafted because the Broncos believed he was a decisive runner who could flourish in their offense as a lead back.

But Ball's injury affected him and his confidence seemed shaken early in the season as the Broncos' struggles in the offensive line showed up the most in the team's run game. Until his injury in a Week 5 game against the Arizona Cardinals, Ball had games where he averaged just 2.9, 2.7 and 1.2 yards per carry.

For the season the Broncos' running backs were hit at, or behind, the line of scrimmage on a third of their carries. The Broncos moved three players on the offensive line in their ninth game of the season, including taking All-Pro guard Louis Vasquez and moving him to right tackle. Anderson was the starting back in seven of the games after the moves were made.

Hillman is a wild card. The Broncos, since he was their third-round pick in the 2012 draft, have consistently touted his explosiveness and big-play potential. But either because of injury or a lack of focus at times, he has yet to top 106 carries in any season.

In the end, Kubiak likes the youth at the position overall and with Juwan Thompson a possibility as a fullback/running back hybrid in the offense, the Broncos have four running backs (Anderson, Ball, Hillman and Thompson) who are 24 years old or younger. Hillman is the most experienced of the four, now entering his fourth season, but he doesn't turn 24 until mid-September.

"With me looking from the outside in, I think all three of those guys (Ball, Anderson and Hillman) have all kind of had their little spurts of success with the club when they've had their opportunity," Kubiak said. " … The fact that they are young -- I like that. So we'll give them all a chance and see how it pans out. Obviously C.J. had a good head start on things."