How can i gain muscle for football?

I havent played football on a team for about 3 years this summer i want to get a headstart.I'm 15 6'0 weigh in at 230.I know football is a ruff sport when i was 13 and played i always got my stomache ab's and chest area hurt since it was weak does anybody have any ideas to stregthen their i'm doing 200 sit ups a day and 2 sets of 50 weight bearing sit ups with a 25 pound plate i'm seeing good results with that.I'm going to be joining a new gym MY main goal is to gain some muscle so i can take the abuse on the field.i know i am about 30 pounds overweight do you think i should lose it first if i am going to play football this year? i know once i get to the workouts with the team i will lose it within 2 months they run full pad exercises and do 2 a days and lift weights 3 days a week.do you think i should lose the 30 pounds first? and any good ideas to pack on some muscle and bring my bench press up bench is my weakest i am not weak but cant even do two 45's on their yet.