Lots of things can cause diarrhea. In such a young pup, I'd make sure he's been wormed and has been given a clean bill of health from your vet.
Stress can cause diarrhea, or even too much food overall will cause loose stools. If your pup has recurring diarrhea with one particular food, it may also be a food allergy to one of the ingredients in his kibble. You can give him boiled chicken and cooked white rice (equal parts) for a few days to settle his system, and then see about slowly starting him on a different kibble.
I would have to agree with everyone else that Science Diet qualifies as a low quality kibble and would do some research on a better food. You may want to use the search feature here (little blue button in upper right) and use keywords like "Science Diet", "premium kibble" and "Whole Dog Journal". Science Diet may be "vet recommended", but the ingredient list on the back of the bag is less than stellar and that's what counts.
Best of luck with your little guy and keep us posted on how he's doing!
Gloria, Mommy to:
Buster the Boxer (9 yrs)
Daisy the Awesome Aussie Mix (2 yrs)
Christopher, Benji and Jonny