Training camp battles aren't a new thing for Dolphins running back Lamar Miller.

In his first two seasons in the league Miller had to battle 'Fumbling Dan' Thomas for reps in the running game. Then in 2014 he squared off against the oft-injured Knowshon Moreno for backfield touches. And through these competitions Lamar Miller has always been the last man standing. But the battle he now faces in 2015 feels a bit different.

That's because, as they say, hell hath no fury like a running back scorned.

In selecting Jay Ajayi with the 149th overall pick in the fifth round of this year's draft, the Dolphins not only got themselves a talented tailback that has drawn favorable comparisons to Marshawn Lynch but also who is a highly motivated player determined to prove everyone wrong for passing on him.

Ajayi presents a legitimate threat to Miller's position on the depth chart thanks to his size and every-down skill set -- even though Miller is coming off a 1,000-plus yard rushing season. Ajayi was the first back in FBS history to rush for at least 1,800 yards and catch another 500 in the same season.

And neither of these backs are without their flaws as well.

With Miller showing signs of slowing down late in games last season, alongside long-term concerns about the durability of Ajayi's surgically repaired knee, the gamut of possibilities for how touches in this backfield will be divvied up span either Miller or Ajayi claiming the lead back role outright to a full-blown running-back-by-committee situation.

Either way, it looks as though we have a heavyweight title bout on our hands with the Dolphins, with plenty of shots being exchanged by both these backs this offseason.