Indianapolis Colts: Position Breakdown and Depth Chart Analysis at Running Back

Running back went from a roster weakness over the last two seasons to potentially a strength for the Indianapolis Colts over the offseason.

Of course, that much was accomplished simply with the release of former third overall pick Trent Richardson, who had become a bit of a problem on and off the field in Indianapolis. For all of the excuses about not learning the playbook, adjusting to the cold winters and seeing eight-man boxes, Richardson simply brought the Colts' offensive effectiveness down over the course of his Indianapolis career.

The rest of the running backs on the Colts roster in the last two years were able to find plenty of success, but Richardson never was able to find that role the Colts envisioned for him when they made the fateful trade in 2013.

But now, Richardson is in Oakland, and the Colts have brought in new faces, young and old, to help transform the running back position into an asset.

The Starter: Frank Gore

It all starts with free-agent addition Frank Gore, a legend in his own right in San Francisco for years and years. Gore, along with Houston Texans wide receiver Andre Johnson, came to Indianapolis to win a Super Bowl despite having opportunities elsewhere.

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Gore will accept a smaller role in Indianapolis, where Andrew Luck and the passing game are the focal point of the offense. In San Francisco, Gore was the man for his entire career, averaging over 250 carries per year since becoming the full-time starter in 2006.

In Indianapolis, meanwhile, the last back to run the ball over 250 times was Joseph Addai in 2007.

Still, the Colts view Gore as the lead back by a wide margin at this point, and while they will likely limit his snaps in order to save his legs for the postseason, the veteran will be the go-to back in 2015.

Most see this as a fantastic get for Indianapolis, as Gore represents a consistency that the Colts have lacked for years at the position. A consistent run threat could do wonders for the Colts offense, which bogged down into one-dimensional play too often last season, though the opening up to a vertical offense was a welcome switch from Pep Hamilton.

Gore should have no troubles fitting into the Colts' running game, however, which has a lot of similarities to the 49ers' system under Greg Roman. According to head coach Chuck Pagano, Gore has fit in seamlessly so far in Indianapolis, bringing a steady, veteran presence to a young running back group, per Kevin Bowen of Colts.com.

Some have questioned Gore's potential effectiveness because of his age, and it's certainly a valid concern.

Having just turned 32, Gore is already past the age where most backs begin to wear down. Some would say we've already seen it from Gore, with his yards-per-carry average dropping to 4.1 and 4.3 over the last three years, well below his career average of 4.7.

But Gore was also stuck in a dragging offense over the last two seasons, as quarterback Colin Kaepernick hit a wall, and opposing defenses focused on the run game. Gore is no longer a spring chicken, but he did manage to have the 10th-highest rushing DYAR of any running back last season and was 13th in DVOA, per Football Outsiders.

If he can be that efficient as a runner when defenses are keying on him, there's plenty of reason to believe that he can be efficient in Indianapolis, where every back not named Trent Richardson has averaged over 4.5 yards per carry in the last two years.

There's also receiving, an area that Ahmad Bradshaw and Dan Herron excelled in last season. Gore has caught just 11 and 16 passes in the last two seasons and scored just one receiving touchdown. Bradshaw and Herron combined for 59 receptions and six touchdowns through the air last year. Can Gore come anywhere close to that kind of production?

I'd lean toward yes. Gore isn't quite as shifty in the open field as the other two, but he's a reliable receiver (just one drop over the last two seasons, per Pro Football Focus), and he understands coverages and NFL defenses well.

Prior to the hiring of offensive coordinator Greg Roman in 2011, Gore averaged 45 catches per season. Since 2011, Gore has averaged just 18 catches per season. The decline in receiving production has been because of of the offensive system, not age.

Gore likely won't have a 1,200-yard season in 2015. That won't be his role in Indianapolis. The Colts don't need him to be a workhorse. They just need him to be an effective option when called upon to keep defenses honest in the run game and provide a reliable checkdown option for Luck in the passing game (his superior pass-protection skills are key here as well). 

Given how undrafted free agents and cast-offs like Ahmad Bradshaw, Dan Herron and Donald Brown have been able to do it over the last two years, Gore should fit into the role nicely. 

The Backup: Dan Herron or Josh Robinson?

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While Gore will be the go-to player for Indianapolis out of the backfield, the Colts will still use a committee of backs to some extent, both to extend Gore's shelf life and to bring different elements to the offense.

With both Herron and Robinson, the Colts get a bit more wiggle in the open field and an ability to force missed tackles that Gore lacks at this point in his career. This is especially true for Robinson, who had Pro Football Focus' second-highest Elusive Rating in the nation in 2014. Robinson forced a missed tackle once every 3.96 carries and finished with 58 total missed/broken tackles in 2014.

This highlights where Robinson has an advantage over Herron in potential playing time: potential. Robinson has a higher ceiling in terms of forcing missed tackles as well as in running between the tackles, where he compares favorably to Frank Gore.

With his potential to be a long-term replacement to Gore, and being versatile with his ability to catch passes out of the backfield, the Colts may want to give Robinson as many carries as possible.

But should Robinson take time to adjust to the NFL, Herron has shown that he can be reliable in a variety of roles. That's his advantage: experience and being a proven product. Herron, while not anywhere near elite, can fill a running, receiving or blocking role at adequate levels, giving him the ability to sub in at any time, as he did late last season.

How the snaps will work out as the season goes on will likely depend on Robinson's development. Chuck Pagano said on Tuesday that he's coming along well, per Colts.com, but we'll know much more come training camp.

The Rest: A Question Mark and Undrafted Players

The battle for the fourth roster spot for running backs will be an interesting one, with Vick Ballard being the biggest wild card. Ballard was a pleasant surprise as a rookie, a dependable option when the Colts needed one to emerge in the running game.

But after ACL and Achilles injuries in the last two years, it seems unlikely that Ballard will be able to return to an effective NFL career. Still, if he can get healthy, Ballard is another well-rounded option who is comfortable in the locker room.

Then there is Zurlon Tipton, a former undrafted player who played some key snaps for the Colts down the stretch last year, including scoring the team's lone touchdown in the AFC Championship. Tipton was often used as a fullback, however, and overall had just 28 total carries for an inefficient 86 yards.

If Tipton makes the roster, it will be because of his ability to play that fullback role, having a bit more power at 6'0" and 221 pounds.

Another player who could have a shot at a fullback role is former Yale running back Tyler Varga. Varga was a standout halfback last season, but he is incredibly strong and willing to potentially make a position change after being picked up as an undrafted free agent. Of course, Varga could always produce as a runner if need be, having run for a 5.6 yard-per-carry average over his college career.

Another UDFA, Abou Toure out of Tennessee-Martin, could have a shot at the roster as well, but it seems unlikely at this point.