My son's HS team (hopefully he will make the team this year) starts their winter workout at the end of September, 3 days a week, not at all mandatory, but gets the boys in shape and gets them in front of the coaches. Tryouts begin the 3rd week of February. I must say that doing the winter workouts is not a guarantee for the boys to make the team, which I like. Last year my son (8th grade) went to the workouts but did not make the Freshman team, we were devastated until a good friend told him that he just wasn't ready to play HS ball- that was the encouragement he needed to work even harder and its paying off!
Now he plays Select ball. After their Fall season, their practices started first week in December, 1 day a week until the end of February then will start back up with practice, games and tournaments as soon as HS ball is over. Of course they have an unwritten rule to hit the batting cages, tees etc. throughout the week.
Basically, my son plays or practices everyday 
He works hard and is dedicated to self improvement and now that he is 9th grade, now we are starting the camps and showcases as money and schedule permit.