This is not to sound any alarms...my 4th child was a wobbly walker but there are other symptoms that go along with that to indicate sensory processing disorder. She has the vestibular and proprioceptor type, where the child doesn't know where his body is in space. Her nerves were sending the signals to her brain but her brain wasn't reading them. She is very clumsy and runs into things. She would constantly choke on her food, too, because she couldn't "feel" how much food she had put in her mouth and properly chew it. She would stuff her mouth so full that she couldn't close it. I don't know if that is your son's issues with food. I found that if I only gave her a small amount on her plate at a time, she wouldn't gag as often.
A symptom of SPD is low muscle tone, which my pedi picked up early on. She has been in therapy for a year, which is really just play on a different level, to keep her from injuring herself. She hasn't been able to figure out how to catch herself with her hands and to use her feet to step off things. It's like she can't figure out what to do with her appendages.
Hopefully, your son doesn't have SPD, but even if he does, it isn't the end of the world, maybe just the end of a major league sports career. But I would look it up on the internet and see if he has any additional symptoms.