I'm trying to gain some musscle mass between now and next football season. Right now im 5'4 and about 134 pounds. I think that is a little small to play high school football and want to try to put on some muscle so I can play. Though I want to gain muscle mass I want to try to keep the deffinition of my muscles. Is there any way to gain muscle mass and keep deffinition at the same time?

Absolutely. All bets are off in regards to what kind of body composition results are possible at your age until you test things out for yourself.

My best advice would be to train and diet in a manner that will allow you to perform at your best in your sport. Explosive, strong, quick, and with a high degree of stamina.

If you want to describe your goals as "bulking" because you're looking to increase strength / add lean mass, that's okay, but I would stop the definition right there. Don't bring a whole bunch of bodybuilding baggage into the mix that will only complicate things.

Yeah you should be golden. When I was trying to gain weight in HS I was really sporadic with my diet. I'd undereat most of the day, and load up in 1-2 meals. So I'd say that you should try to get maybe 5 meals a day in, so before school, lunch, after school, dinner, and something before bed. If you can keep it consistent it'll be easier to go "Ok, I'm not gaining much, I'll add a bit to these meals." No need to go nuts with counting calories or anything. Just try to eat some fruit, veggies, meat, eggs, and oats on a regular basis.

Lifting consistently will be important as well. So get in the gym 3x a week and be sure you're hitting the lifts that work everything. Pullups, squats, cleans, rows, overhead press.

Thanks for all the advice. I'm working out 3 times a week now with my dad. The diet is a little harder. In the morning I eat a protien bar and a banana because they are quick and easy before I have to catch my bus, but I always end up getting hungry. I feel that once I get hungry I end up just trying to eat whatever is quick and easy and I think I end up eating a lot of things I probably shouldn't eat. Can anyone suggest something that would still be quick for breakfast but will help keep my full?

Thanks for all the advice. I'm working out 3 times a week now with my dad. The diet is a little harder. In the morning I eat a protien bar and a banana because they are quick and easy before I have to catch my bus, but I always end up getting hungry. I feel that once I get hungry I end up just trying to eat whatever is quick and easy and I think I end up eating a lot of things I probably shouldn't eat. Can anyone suggest something that would still be quick for breakfast but will help keep my full?
I'd really like to just say "get up earlier," but I can relate, because I don't like getting up earlier myself. :) Still, something needs to be done to change your breakfast.

Since you're using protein bars I assume supplements are not out of the question. If I'm correct in that assumption then I would recommend ditching the protein bar and picking up a protein powder. Try this for breakfast:

-Protein powder
-Oatmeal (ground up in a blender or coffee bean grinder, or just eat it normally in a bowl with hot water)
-Milk and/or water
-1 piece of fruit (so you can leave the banana in the meal)

This should take no longer than 5 minutes to prepare and eat (err, drink and eat) if you're just mixing ground oats into the shake. If you're cooking the oats and eating them from the bowl it'll take a little bit longer, but even then it won't take long. If you're going to go with the cooked oatmeal route, just take a bowl, add oatmeal, add water, and toss the bowl in the microwave. While it's cooking you can prepare and drink the shake.

If you're lacking in fats throughout the day you can add some kind of oil to the shake (olive oil, Enova oil, flax-seed oil, etc.). 1-1.5 tbsp. probably won't make it taste bad. You probably won't need to do this though, just add some almonds, peanut butter, oil, etc. to other meals.

Well you have 9 months to prepare for next football season. You could have a bulk/cut/bulk cycle in that amount of time. I wouldn't worry about looking great going into 2 a days. I'm sure those will lean you up quite a bit, so go ahead and use that to your advantage and hit training camp at your strongest.