I think Javy knows that, but he may simply be poor at differentiating sliders from fastballs, or he may be poor at reading pitchers moves while in the box. It might be a physical thing. I think he'd like to be able to lay off those if he could, I mean, who wouldn't, but maybe he just can't because there's some physical shortcoming he has that can't be fixed. If this is the case, it might be a vision issue.