I've been working on my tee for some time now and I used to hit them straight to center or center right or center left. Now all my swings result into huge line drives to left field or homeruns over left field fence. My daddy says that I need to learn to hit to right and center more often. Im right handed by the way. These swings started going to left after I started doing core exericise and started working out (off season training). I don't know if that has anything to do with it but I don't think my swing has changed in this last week.