I do the same thing when I can. When I was playing on default all-pro, I remember causing Darren McFadden to fumble on 3 straight running plays(obviously in different series though) and that just wasn't going to work for me.
For the slider set I've since made for myself though, I believe I've got CPU fumbles at about 75 or 80 and that has cut down on a lot of their fumbles. So, I'd recommend that for anyone having this issue.