I can start you in the right direction, but you will have to do a lot work on your own to fill in the program for the player you are putting this together for. (Unless you go pay someone to do this for you) FYI, I am not a strength and conditioning coach, but have put a program together for my son who is a HS pitcher from various sources.
First go to the strength and conditioning section and do a search on workouts, pitcher workouts, etc. This will give you some ideas on where to start.
For a pitcher the legs and core are the focus area. (core not just meaning sit ups) I have heard good things of the Tuff Cuff program but don’t have the book. I do have Jon Doyle’s unbreakable abs and this will give you start for a core program. You can fill in from there. Make sure the program has a lot of Olympic lifts with compound moves and as Jon Doyle says, “make the squat rack your friend”. Add in some Jobe exercises (do a look up on “throwers ten” program here and add in those exercises.
Find a sprint coach and work in some sprinting in between the lifting. I would suggest the fall be the time for the heavy weight/core training, with no throwing for at least 8 weeks, some say 12 weeks.
I am a long toss bigot and think Jaeger sports has the best canned program you can find. (and afford) Get his bands and make them part of the daily work he does.
Be prepared to do a lot of research and build the program around the time the player has in between school, life, and baseball.
Good Luck!