Can't speak for dbg_fan but my son's situation was probably a lot like his son except his son had a good chance to get in without baseball. Josh hadn't taken the SAT at all in HS because the schools he had been looking at were okay with the ACT. I know for a fact he didn't get close to the SAT mean for admission into Dartmouth. He did however have everything else needed for admission including a glowing coaches letter. That said, admissions does rule the roost and if they feel that the student would still have problems they would probably be rejected. I feel very strongly that without the baseball aspect my son would not have been accepted.
There is assistance if needed. My son's first email home was that he was the "stupidest" kid on campus. After talking with other parents they said that was also the first email they got from their son's. There are students who definitely excel and there are others (like my son) who had to work their tails off to succeed. A kid's make-up is very important as it's definitely not for everyone.