Much has been written on this website about academics v. athletics, and I believe it is always a most appropriate topic, as the ultimate goal is finding the right/best fit for our kids.
See this thread:
http://hsbaseballweb.com/eve/forums/a/tpc/f/4686003481/m/5021082392/p/1IMHO, if I had to sum it up in one word, I would probably choose "balance". But balance to the highest possible level. Academics at the HS level is different at all HSs in all georgraphies, and even within the same geography. Some offer AP/IB beginning in Soph year, some don't have any or very few. Colleges know the academic status/offerings of all HSs in this country. Each college has AOs who are assigned most usually by geography, and it is that AO's job to KNOW their HSs, and they really, really do -what the HSs offer for courses, whether the HS suffers grade inflation (this shows up via standardized testing), etc.
So, have your student take the most rigour he/she can/will commit to handling that is offered at your HS. If that is all APs, then go for it (IB is another format similar to APs, some schools have either, some have both). If not, then find the best balance where there will be a mix of high grades and strong academics - to keep grades good, but at the same time show challenge. It is a catch 22 because colleges want to see challenge (they will tell you they prefer Bs in AP or Honors classes to As in regular classes), but you need to get the grades to get in. If the student cannot acomplish this, then take those classes that they can handle comfortably (with just a little on the challenge side). Obviously, baseball (or any sport or EC activity) must blend into this balance.
A student who gets Cs and Ds in freshman year can show several things, all of which can be explained to or taken into account by an admissions officer. However, a student who continues to get Cs and Ds throughout HS I don't think would be a candidate to play ball at a 4 year school to start with, no matter whether he is the next coming of Babe Ruth or Willie Mays, because a 4 year cannot risk losing schollys because it cannot make its rating. As 44 says, JUCO would be a great route.