Here we go again.
Wait, so you want to stay as small as you can for baseball? Why? It's not like baseball is a sport where there are weight classes (like wrestling, or weightlifting) or even being small is an advantage (like gymnastics). Dear God why do you want to stay as small as possible?
You mentioned Clemens, definitely one of the most successful and dominant pitchers of all time. Have you ever actually looked at Clemens? He is a pretty big boy. You know why he has had so much longevity? Because, first he's just got the genetic make-up to do it, second he's been lucky enough to not get any career ending injuries, and third because due to his mass he can get a lot of velocity on the ball without trashing his arm. He would not have lasted as long and been as dominant had he been small.
If you had a good reason to stay small I could see your line of thinking. But, you really don't seem to. Honestly, putting on some muscle and improving strength are probably going to be of great help for you.