A research article was recently published in the Journal of Shoulder and Elbow Surgery discussing rest from throwing in the off-season and elbow injuries in elementary aged baseball players. The age range was from 10-13 years.
The researchers did an ultrasound on the elbows of throwers, chunking them into categories of <1 month of rest from throwing, 1 - 2 months of rest from throwing, and > 2 months of rest from throwing.
The study showed that there was a direct correlation to elbow pain and joint abnormalities in the cohort that had less rest from throwing during the recommended off-season. The < 1 month of rest group had significantly higher incidences of elbow pain and injury then the 1 - 2 month and > 2 month groups.
A few key factors for health and longevity during these early developmental ages are playing multiple sports and getting rest from throwing. This is difficult when your son or daughter is at an elite skill level for this age group and is requested to play in specialized tournaments throughout the year instead of getting that much needed rest.
This brings me to another article recently published showing that the biggest reason for shoulder injuries in little league baseball players was early specialization, year round throwing, and playing on all-star teams. This is two totally different studies showing basically the same thing. It would be in you and your child's best interest to listen to this advice and not chance the injury bug.
I would much see a throwing athlete in my office for occasional arm care and performance therapy rather than rehab for an injury that could take them out for weeks, months, or even a year. Taking rest seriously during these important developmental years is insanely important. If you're really into baseball or softball, please try to not specialize solely into that one sport until at least 16 years of age. Not only is it important for health purposes, but motor control and performance reasons as well. So whether you play fall baseball or not, please try to find the time to rest from throwing, your body will thank you!