The competition comes from not only how the coaching staff uses the duo, but from the mouth of offensive coordinator Mike Sherman, who illustrates the competition as “neck and neck” per Adam Beasley of the Miami Herald:
According to Armando Salguero of the Miami Herald, practices have given no hints as to how it will shake out. Thomas received 12 snaps in 11-on-11's with Miller receiving just nine. "Neck and neck" sounds about right.
Part of the caution from the coaching staff toward Miller has to do with his spotty injury past, including a recent ankle scare in training camp. Add in a fumbled handoff during the Hall of Fame game and dropped passes and it is easy to see why Miller is seeing fewer opportunities than Thomas in the preseason.
Or is it Miami truly believing in giving both Miller and Thomas even carries next season?
Dolphins general manager Jeff Ireland seems to be thinking along those lines, as he told the media per Barry Jackson of The Miami Herald that “I don’t think it’s just going to be Lamar’s position. We’ve got a good running back in Daniel Thomas that’s certainly making some noise.”
Not to discredit Thomas, but Miller has more to offer and should see the field more next year. First, let's gander at the production:
Thomas has failed to ever break four yards per carry in two years, which is a good measuring stick to go by when evaluating running backs. Anything less is a disappointment and Thomas' 3.5 in 2011 on 165 attempts speaks volumes.
Conversely, Miller notched a superb 4.9-yard average last year, albeit on just 51 attempts.
What really sticks out is Thomas' four touchdowns on only 91 carries in 2012. He is an effective short-yardage back, especially in the red zone. If the Dolphins were to use Thomas in that capacity while giving the majority of the work to Miller, things would work out.
Miller is a known commodity despite only being a second-year player. He does well with pass blocking and will stop on a dime and use his elite speed (4.4 40-yard dash) to get into open space where he does the most damage.
Thomas, on the other hand, struggles in pass protection and other areas as evidenced by his No. 48 ProFootballFocus (subscription required) ranking on a list that graded 51 players.
The Dolphins are protecting Miller because of injury concerns. At a time when most teams are revealing their hands in a preseason Week 3 "dress rehearsal," Miami is playing it safe with a back that figures to play a pivotal role in the team's success in 2013.
It makes sense Ireland wants Thomas to succeed—he traded up in the 2011 draft to nab him. Five fumbles later and with a 3.5-yard average, Thomas may have played himself out of a starting role—hence why he is in a competition with a fourth-round running back in the first place.
Miller is an elite talent who has had trouble staying healthy. When it matters most in the regular season, it will be Miller's talent rising to the top of the depth chart. Miller must start if the Dolphins want to make some noise in the AFC East.
Follow B/R's Chris Roling on Twitter for more news and analysis: @Chris_Roling