to get him to not be afraid of the inside( im a QB) have him play a bit of runing bac at practice have him run up the middle(thats how i got my fear of the middle off my bac).

good advice greg. I'll only add have him thank the line after each block he gets as he repeats this he will enjoy the role of being a leader and not only will he have a impact on there game he will begin to trust the offense to be with him.

teach him to get his shoulders down and knees up. The hardest part about running inside (especially for sprinters) is the tendency to run straight-up. This will get him hurt when he starts running through traffic. Once he feels strong and protected in his running technique he won't be as intimidated to run inside. If he can't get the running style correct - i wouldn't force him inside - he'll get hurt - find someone else