I think this topic will always come up here at the hsbaseballweb. Excellent comments thus far...
I have no doubts politics exist at some level in every organization or endeavor. It is part of the human condition imho. With respect to baseball, there are some tools to overcome politics:
1) You cannot control the coach's decision so never discuss politics with your son. Encourage him to lay it all out on the line and let the chips fall where they may. If he comes up short, encourage him to be the best team player on the planet and be prepared for future opportunites.
2) Versatility can defeat politics. If you are a shorstop and the coaches son is a shorstop, it might be a tough gig to beat that kid out. If you can slide over to second or third, you have tripled your chances of playing. If you can play outfield, you have increased your odds even more.
3) For non-pitchers, if you can hit they will find a place for you in the lineup.
4) For pitchers, throw strikes and let the chips fall where they may. It is hard for a coach to have confidence in a kid who is afraid to throw strikes imho.
5) Only focus on those things you can control like...
a) first to arrive last to leave
b) have the best attitude on the team
c) be the hardest worker on the team
d) have the dirtiest uniform on the team
e) be the guy who hustles the most
f) be the best teammate
g) do any team dirty work that might need done like field maintenance, carrying the water cooler, shagging balls, picking up equipment, etc. etc., etc.
h) never hang your head
l) always concern yourself with your teammates first
These things can get you noticed and help you stand out in a crowd. Never ever make excuses. Even though politics may exist, never let it be an excuse. A big part of baseball is learning how to overcome the excuses.