I would say for a kid with good to great athleticism who clearly stands out compared to his peers - it doesn't make much difference at all.

Here locally - I have to say that I noticed that the coaches all talk to each other - and the little league coaches tell the HS coaches who the best players are from the beginning. So if there are a couple of kids who seem similar in the measurables, but the little league coaches have told them that one kid performs better than the other - guess who gets the benefit of the doubt when it comes to reps in practice, and ultimately in games...

For a kid who is starting out in HS, it can be hard to break into the lineup. They don't have experience hitting with pads or catching with pads, getting hit, etc., and it isn't uncommon for the coaches to make some quick decisions in order to get more time up front installing a playbook with guys who are ready to go now.