Welcome to the boards. Also have a 15 YO sophomore son who was throwing low to mid 80's last year. His only other pitch is the slider, which is due to his natural delivery. Not sure what he will be throwing this year, but he is still getting bigger, quicker, more agile and stronger. He decided to take this year off to concentrate on basketball. When the weather turns decent, we'll do bullpen two to three days a week at the local high school, assuming I can still catch him. Otherwise, I need to find a catcher for him so he can continue to develop. The Varsity coach wanted him to pitch varsity this year, but my son said no. Unfortunately, he's through with organized baseball for the present. Basketball has become his passion. It's exciting, fun to play (i.e. dunking), fast pace, continuously moving, etc... In baseball he's always dealt with coaches who play favorites and tell him to pitch easy so they can hit it.
Always interested in how other kids my sons age are doing. Best baseball experience he's had was playing in a 15U AAA tournament in No Cal on his 13th birthday. He hit .750 for the weekend and his slider invoked grounder after grounder against the winning team. He was used to striking out everyone, but in this tournament, he knew his FB wasn't big enough to get the strike outs, so he went with the slider and used the 2-seamer to keep the better hitters off balance. I believe he went six innings and only had 2 Ks. Everything else was on the ground.