Your actual question is so specific to 15U in Fort Worth, maybe someone here can help with that part. A tall and left-handed kid will always be pushed towards the mound. He will make that team if the coach felt he could use him in middle relief perhaps. I would get him with a pitching coach this spring along with his work on hitting. If he is a right-handed hitter you failed him like I failed my son. My advice is to work with a pitching coach. Of course, you will get a lot of advice to work on strength (bigger, faster, stronger) and that is 100% correct too. Good luck.