He is:
Cheap
generally available, especially given his workload
solid ball security
can competently run, run routes and catch, and block, and I'd say he's a bit above average at each
I don't think any team benefits from signing RBs to big long term deals, so these are the traits I look for. Don't invest much, draft an RB in rounds 3-6 every other year, sign cheap guys to fill in the gaps. It's rare that RBs are anywhere near elite value on their second deal, and even if they are it's a position that is usually very dependent on other players.