My son is a pitcher and is seventeen his diet is poor and i would like to know if whey protein would help ?

Not really: If your son's diet is poor (i.e., lots of junk food and snacking), then he is probably lacking proper vitamin, mineral and fiber intake. For this, encouraging more fruits and vegetables is important. In a pinch, if you can't get him to increase fruits and veggies, a multivitamin can be helpful to supplement his diet. Whey protein is simply additional protein intake, and he doesn't need that.

Might help but also: Whey powder is a good source of protein, which is important for building and maintaining muscles. I advise whey from grass-fed cows not given hormones & antibiotics. He also would benefit from vegetables & fruits- if he does not eat these consider something like orac-energy greens, which has extracts of vegetables, fruits, herbs and superfoods. If pitching is important to him he should eat better!