I think you'll find the term "high academic" gets thrown around a lot. People's definition varies. For HA, I look at what is required to get admitted in as a student (not baseball player as you phrased your question) through the general admissions process...lets call that the "Admissions front door". In my son's experience, the part that varied the most is how the Admissions process worked for the recruited athlete...lets call that the "Admissions back door". Again, my son's recruiting experiences across D1, D1 Ivy, D1 Patriot and D3 HA schools varied tremendously in terms of what influence the coach had with admission or what admissions required of their recruits. Getting back to the question, I'd have to put a metric down of admissions percent for a HA school. I'd say 15% admitted percent as a high water mark for starters. That would be my stake in ground. Others may think differently and I'd like to hear what they have to say.
So, I'd break this question up and look at what it takes (https://nces.ed.gov/collegenavigator/) for the various HA levels and examples I'm throwing at you: Stanford, Duke, Vanderbilt, Richmond, William & Mary, Harvard, Cornell, Lafayette, Amherst, Tufts, Case Western Reserve, Emory, Trinity, etc. After you have a sense of their admission metrics then start asking the hard questions to yourself and the recruiting coach: Do these schools require the same academic metrics as the generally admitted pool of candidates. If not, how much of a recruited athlete discount do they get from the generally admitted pool of candidates. The coaches know how much academic margin they have with Admissions. It is also a good idea to ask about their process and timeline.
As for an HA Showcase, I think there is a lot of leeway as some students have yet to take the SAT or ACT. If your son is an honor roll student, top 15% of his class, with some AP courses. I think that is a good starter, and welcome anybody to tell me different.