Not that's it is a position of need this year, but with the R&R Express likely to leave town soon, it would be nice to have some power behind the throne...
Yes, but not only is Sheets not the answer in my opinion, but running backs are dime a dozen so it's not like you have to hoard what you have now for later.
Even if both RB and RW leave after this season, next year's draft is not slacking in the running back category:
Noel Devine, Evan Royster, Brandon Saine and my personal favorite; Derrick Locke.
That's just the seniors. Guys like Mark Ingram, Caleb King, Quizz Rodgers, and Ryan Williams could all enter the draft (if memory serves right anyway.)
While I'm thinking about it, I'd love to have Saine and Royster. They could probably be had in rounds 2-4. Suddenly Miami has another 1-2 punch, at very little expense.