Size means everything. Bobby Petrino sat me down in his office and said if I weighed 235 pounds by the end of my senior year he would offer me. I never got above 210 (but David Marmon at ISU got me to 260 lol).
This kid is probably more of the same, they may offer him a grayshirt to get him in as a KR specialist but I doubt he would get a serious look at RB in the very beginning. If he destroyed on scout team his first two years he may find a place in the rotation at a big school, but I don't see him ever being a feature back. For every Maurice Jones-Drew there are 100,000 Maurice Jones-Drew-esque running backs that never do anything because of their size.
Offer him, send a call a week his way and see what happens. At 5'7 you shouldn't be looking at getting playing time, you should be looking at going to the best school you can go to, even if it means not having a scholarship for a year or two.