With Sproles Gone, Who Fills His Roles?

Darren Sproles had multiple roles on the team and they all need to get filled somehow. The punt return duties might go to Antoine Cason or Patrick Crayton. Last year Cason took it over, but do we really want to have our starting corner returning punts and risking injury on special teams?
For kickoff returns, I would assume it would be the same 2 guys and maybe one of the undrafted rookies make a run at the position during preseason games. One of the drafted rookies like Vincent Brown and Marcus Gilchrist may be given a shot also.
Who will be the third running back on the team? Right now it would be Jordan Todman, but we should probably look outside to bring in a veteran to fill that role. Todman may be a good back in the future, but he needs to learn the system and gain some experience. Maybe we can look at possibilities like Ronnie Brown or Clinton Portis. Both should be cheap options and have the experience under their belt.
What do you all think?