True. The game describes it in the sliders settings from the main menu (for some reason, you don't have any slider description if you are changing them in franchise). The higher you set the "fumble" slider, the less your players will fumble the ball.
Also, you should look at the simulated stats in franchise. There are very few fumbles recovered by other teams. So keep that in mind. You may want a realistic number, like in the NFL, or a fair number compared to simulated teams in franchise.