DAVIE (CBSMiami) – Most of the focus for the Miami Dolphins and its fans ahead of free agency has been on the offensive and defensive lines. But running back is another position the Dolphins may address either in free agency or in the upcoming 2014 NFL Draft.

The Dolphins currently have Lamar Miller and Daniel Thomas as its top two running backs. Both have largely been disappointments since being taken highly in each of their respective drafts. There are a few good running backs available, but the question is cost.

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Teams don’t spend a lot on running backs with a lot of tread on the tires because using a fourth or fifth round draft pick on one is much cheaper than signing a free agent. Still, with limited draft picks and so many holes to fill, the Fins might shop for a little running back help in free agency.

At the top of the free agency list is a running back who was a disappointment until the 2013 season, Knowshon Moreno. A former first round pick, Moreno began to improve as the 2013 season wore on and shouldered much of the running load for the Denver Broncos.

Last season, Moreno ran the ball 241 times and gained 1038 yards and 10 touchdowns. He only had one fumble on the season and his pass blocking improved out of necessity because he was helping to protect Peyton Manning on many downs.

Interestingly though, Moreno struggled against teams in the Broncos’ division, gaining just 2.9 yards per carry and scoring zero touchdowns. When he played teams outside the Broncos’ division, Moreno gained 5 yards per carry and scored all of his 10 touchdowns.

Behind Moreno is Donald Brown who finally started to come into his own with the Colts last season. Brown averaged 5.3 yards per carry, but only carried the ball 102. Still, Brown ran for 537 yards and scored six touchdowns on the season against no fumbles.

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Brown got better as the season wore on with his best rushing month coming in December when he averaged 4.7 yards per carry on 45 attempts and scored three touchdowns. Still, Brown has never lived up to his top billing as a high draft pick, just like Moreno.

One running back to keep an eye on will be LeGarrette Blount. The former New England Patriots running back was a solid running back last season rushing 153 times for 772 yards and seven touchdowns. His 5.0 yards per carry would be a welcome addition to the Dolphins offense.

Blount is a 250 pound smash-mouth running back who has a bit of speed to match with his tough-running style. Blount also has a tie to the Dolphins as the new Fins GM Dennis Hickey lobbied to get Blount in Tampa Bay when Hickey was with the Buccaneers.

In two games against the Dolphins last year, Blount ran the ball 22 times for 93 yards, or roughly 4.2 yards per carry. Against AFC teams last year, Blount ran the ball 113 times for 585 yards (5.2 yards per carry) and six touchdowns. He also gained six first downs on runs against Miami.

But, Blount struggles in an opponent’s red zone. Last season, Blount ran the ball 24 times for 67 yards in the opponents red zone.

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The options are plentiful in free agency and in the upcoming draft, but if the Fins go into the draft looking for running back help, it likely won’t come until the third day of the draft.