We had the misfortune of having my son royally sprain an ankle in a tournament on the eve of a camp at a school he was very interested in; he checked in and went straight to the trainer for more ice. Not good. The school was wonderful about it but his chance to make an impression vaporized as he couldn't even run for two days and forget throwing off of a a mound.
Yesterday I saw a young man pitch in a tryout for a team, with plans to immediately after head south for a showcase that begins today. A good looking pitcher, but in his second inning, the hitters got on a roll (every pitcher's dad has seen this one) and he threw 45-50 pitches; no way is he ready to showcase today.
Moral of these stories: be careful of your son's schedule shortly before important events, and give your son the best chance physically to impress. You really do only get one chance to make a first impression.