I can feel your pain. Your are in a tough spot. But, remember, in the end, it will be their decision as to what path they choose to travel. My oldest, no prob, baseball all the way. Middle son, was in the same grey area as you described. I was not sure if he would stick with baseball. Has all the talent and size, but not exactly motivated. Fortunately something clicked last year when he was in 8th grade and things changed, he was suddenly motivated after a few of the kids he had played with the year before made JV, and he knew he could out play them. It also did not hurt that his older brother started pushing him. I've seen a lot of kids burn out around that age, girls, x box, etc... That's when you have to ask the toughest question of all....WHO really wants it, you or him. you can only do so much for him. Maybe you could drop the hammer on the x-box, limit the time to an hr a night. Then maybe you can ad some incentive time if he puts in the extra work like t-work, or soft toss. I had to do that with mine for a little while. Plus, you need to let him know that his HS season is a lot less than 14 months away, it is more like 7 mo's...the HS team should run a summer program and it is a good idea for incoming freshman to participate, get their face in front of the coaches and get to know them a little.
Good luck