We have gone from a situation of waning confidence in his abilities and burn-out from an exhausting season played in a city just over two hours from home. That was three years ago, and I coaxed him into continuing on a weaker team a couple of years older and that was close to home. On this team, he had the opportunity to work at different positions and his hitting. He had a lot of fun. His body started to change that summer and the next year, he went back to a higher pressure situation. From there he was picked up by a top travel organization.
We certainly pushed the situation to continue. We also emphasized different things that season (more character building with his team than anything else). We also continued to get him in to periodic high level training sessions (which was a no-pressure way to keep his skill levels up - in fact they advanced). One key component to this though was that he became a more dominant player and his self-confidence rose. His work levels have escalated in the years since. The burn out had more to do with the lost confidence than the exhausting schedule. He walked away from the whole thing with a feeling of having "overcome" an obstacle.
Your son has lots of time. I would find a light load team to play on and the best possible instruction possible with the idea of playing on that High School team next year. At the end of 2008, I set it up as "Let's give it one last shot". Support him with the best training possible (it's probably far cheaper than running around with a travel team). Any trainer worth his salt will provide better tools and help to boost his confidence. This should manifest itself on the field. My son went on from a 350 batting average to become a hitting technician over a five month period that first winter. He's the same age as your son, I think. He's at about 650 right now and in the #4 spot. I throw a few buckets to him about four days a week. Interestingly, he's been told he will not likely run fast enough to be a hitter - he's to be a pitcher. He still stops in for the odd lesson with the hitting coach and corresponds with him. Go figure... three years ago he was despondent and was ready to put the game behind him... now he works harder than any of his team mates at a skill that in all likelihood he will not use at higher levels.
Right now, the world of "hanging out" looks like a heck of a lot better option to him than working out at a sport that he perceives himself to have failed at. A HS Freshman is not likely going to put himself into activities like the computer club or join the HS debating team as options to fill the gap. My son would be "party hardy" and non-stop Black Ops. Baseball has meant so many non-baseball positives for my son, it's not funny. For one, he finished this year with a 3.5 (absolutely would not have happened without the goals baseball made so clear). It keeps him physically at his best and the girls notice. Ironically the game that takes all his time, gives him a social calender that is jam-packed. I would say twice as jam-packed as the guys he would have been "hanging out" with. On a number of occasions, my son has thanked me for having him "stay the course".