ENGLEWOOD, Colo. --The two players that accounted for 359 of the Broncos' 377 carries by their running backs last year are about to hit the market.

But the circumstances are different for Ronnie Hillman and C.J. Anderson. Hillman is an unrestricted free agent; Anderson is restricted, and the amount of his tender will likely determine what interest he draws.

Anderson also overcame a slow start exacerbated by an ankle injury to turn in a productive season. When factoring in the postseason, Anderson finished with 4.63 yards per carry -- 0.79 yards more than Hillman -- and 4.90 yards per touch, 0.98 yards greater than Hillman. Anderson's first-down rate was also higher; he moved the chains once every 5.0 touches compared to once every 5.5 touches for Hillman.

These are rates that need to improve, but averages of 4.63 yards per rush and 4.90 per rush offer optimism moving forward for Anderson.

"Keeping C.J. healthy I think is a key moving forward," Head Coach Gary Kubiak said last week at the NFL Scouting Combine.

Kubiak also added that Hillman "hopefully" will still be a part of the equation. But with Juwan Thompson and Kapri Bibbs waiting in the wings and a host of other options in free agency and the draft, Denver's ground game might look a bit different his year.

A look at the top free agents set to hit the market at running back:

1. Doug Martin, Tampa Bay:When he's healthy, he's one of the league's most consistent running backs; in the two seasons in which he played all 16 games, he broke 1,400 rushing yards each time. As a rookie, he finished with 1,926 yards from scrimmage and scored 12 total touchdown.

Martin is also one of the most sure-handed running backs in the league, averaging one fumble every 139.3 touches -- although five of his seven career fumbles came last season, when he tallied 1,673 yards from scrimmage and moved the chains once every 4.52 touches, the best rate of his career.

As the No. 2 rusher in the league last year, Martin will have options. Having missed 15 of 32 games in the 2013-14 seasons will give some teams pause, but when he's healthy, he's one of the few true workhorse backs in the league.

2. Lamar Miller, Miami:Miller hasn't been as spectacular in season-long production as Martin, but he's missed just three games in his career -- all as a rookie.

He also had a better first-down rate last year (one every 4.46 touches) than Martin, and a better fumble rate (one every 151 touches). Productive, versatile and durable, Miller should find himself getting plenty of work this season, whether in Miami or elsewhere.

3. Matt Forte, Chicago:Forte is more productive over the long haul than Martin or Miller; the concern is age, although he used deadpan to downplay any concerns about turning 30 in December:

"I'm dead," told ESPN.com "I'm an old man. I feel like I'm so old, man. Yesterday I was 29 years old, running around all practice. Today it took me like one extra minute to get going. It's taken a toll on me."

Although Chicago has made extensive use of him, he hasn't racked up 300 carries in a single season since his rookie year. His total yardage numbers were down, but his per-touch average was right in line with his career pace, and his rate of one first down every 4.16 touches was better than his career average (one every 4.38 touches).

Forte also avoided being stopped behind the line of scrimmage; according to STATS, Inc., his stuff percentage of 5.5 percent (12 of 218 attempts) was the league's best among running backs.

Used properly, Forte still has plenty of juice left, and he brings intangible value as one of the best locker-room presences in the sport.

4. Alfred Morris, Washington:Although durable, Morris' production declined the last two years as Washington moved away from the zone-blocking based scheme favored by previous head coach Mike Shanahan; his production steadily dropped from 4.8 yards per carry as a rookie in 2012 to 3.7 last year.

Morris' fumble rate has trended in the opposite direction; in his first two seasons he fumbled once every 70.1 touches; in the last two he fumbled just once every 247 touches.

Washington's decision to draft Matt Jones last year in the third round seemed to augur an eventual decision to move on from Morris, who could be a better fit and re-discover his early-career form with a change in scheme and scenery.

5. Chris Ivory, N.Y. Jets:Fresh off of his most productive season, Ivory has never failed to average at least 4.1 yards per carry in a season and has improved his pass-catching production in the last two years, with 48 of his 53 career receptions coming since 2014.

Although he posted career highs in touches (277), rushing yards (1,070), touchdowns (eight, including one on a reception) and yards from scrimmage (1,287) last year, his first-down rate declined; he moved the chains once every 4.69 times he touched the football last year, a decline from his previous rate of one first down every 4.25 touches.

6. Mike Tolbert, Carolina:One of the best fullbacks in the game, Tolbert is also a threat with the football, although an uncharacteristic fumble in Super Bowl 50 sullied his season. Tolbert had not fumbled since 2011 before losing the football in that game; it spoiled a season in which he not only delivered solid work as a blocker, but chipped in 410 yards from scrimmage and four touchdowns on 80 total touches.

7. Chris Johnson, Arizona:In his eighth season, wear and tear caught up to Johnson as he did not see any work after Week 12. In the games he did play, he averaged 79.3 yards from scrimmage per game, although his first-down rate of one every 6.31 touches was disappointing. If the Big Red brings him back, it is likely to be as a backup to emerging 2015 draft pick David Johnson.

8. Bilal Powell, N.Y. Jets:One of the league's best at catching passes out of the backfield, he racked up 47 receptions for 388 yards despite playing just 11 games, and averaged 5.99 yards per carry while moving the chains once every 3.0 touches (once every 3.89 carries and once every 2.24 receptions).

9. John Kuhn, Green Bay:Kuhn remains a Wisconsin cult hero, but showed signs of the wear and tear from 10 seasons on active rosters and 11 in the NFL overall; he was less effective as a run blocker than he had been in previous years, although he did not allow a sack for the third consecutive season, per ProFootballFocus.com. He's also become less involved in the offense as a ballcarrier and receiver; his 15 touches last year were the fewest he's had since 2009.

10. Khiry Robinson, New Orleans (RFA):A horrifying fractured tibia brought an early end to his promising season. In New Orleans, he served as an ideal change-of-pace back from Mark Ingram and C.J. Spiller, and he appears likely to return.

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Other UFAs of note:**

Joique Bell, Detroit
LeGarrette Blount, New England
Ahmad Bradshaw, Indianapolis
Bryce Brown, Seattle
Reggie Bush, San Francisco
Shaun Draughn, San Francisco
Lance Dunbar, Dallas
Tim Hightower, New Orleans
Fred Jackson, Seattle
Will Johnson (FB), Pittsburgh
Bobby Rainey, Tampa Bay
Stevan Ridley, N.Y. Jets
Jacquizz Rodgers, Chicago
James Starks, Green Bay
Pierre Thomas, Washington

RFAs of note:

Derrick Coleman (FB), Seattle
Benny Cunningham, Los Angeles
Jovorski Lane (FB), Tampa Bay
Christine Michael, Seattle