Think about like the NFL. Elusive backs generally are change of pace guys who don't get enough carries to fumble the ball, with the exceptions who are well....exceptional. your player can probably be an effective roleplayer but given his imbalances he will doubtfully ever be a workhorse. That being said, I don't know how many carries per game you're getting, but if it's higher than 15 than that's probably your issue. It also probably depends whose hitting you...if a lot of hard hitting linebackers are hitting you play after play, then it's no surprise that you're fumbling given your confidence handicap. I don't think you should start over, maybe just find a different fit for your guy. If he learns to catch and becomes a receiving back, maybe he won't be taking so many hits from linebackers since he'll be out in space, and that's a skill set that goes well with elusive running anyways. It's only season one and I think it's harder than people make it out to be to make an unfixable or broken player
