Signing Knowshon Moreno to a one-year, "prove-it" contract could be a great move for the Dolphins. In a best-case scenario, he would, indeed, prove it and earn a long-term deal, like cornerback Brent Grimes last year.
Regardless, there are major question marks about the viability of running backs Lamar Miller and Daniel Thomas, who is scheduled to hit free agency next offseason.
Tre Mason could be described as a jack of all trades but a master of none. He has great vision to find the hole, and he hits it at full speed, using his quickness to elude defenders along the way. He has excellent stop-and-start quickness that allows him to watch as defenders brush past him before he hits that second gear and breaks off a nice gain.
He is a tough runner, absorbing contact and sometimes spinning off it. He is short and stocky with a low center of gravity and built-in pad level at 5'8" and 207 pounds.
Make no mistake: He can contribute in the passing game. He caught only 19 career passes at Auburn, but he flashed playmaking ability with the ball in his hands. Even if he doesn't contribute as a receiver, he is solid in blitz protection, and that can be just as important.
There's one concern: He has 535 combined touches in the past three years, so the tread may already be thin on those tires, but that also means he has even more experience against top-notch SEC competition.