I started thinking of this topic because
Yesterday I went to a varsity High School game where the pitcher did a fairly good job through the first four innings.
( was told beforehand she only has four innings in her and sure enough the first pitch of the fifth inning it was obvious she was done)
They really don't have another pitcher.
The other teams start crushing at this point.
And the terrible team defense gets exposed. (they can handle dribblers, not shots)
My solution thinking is immediately change strategy and resort to something like 50% to 75% change ups and hit the farther off plate edges with wild'ish pitches.
There going to have to try something.
Every pitcher should have a good or usable change up.
Think there are times its the best weapon in the arsenal!
I've seen several pitchers that threw mostly offspeed with a fastball as just a secondary pitch. I don't see those pitchers lasting deep into 18u territory. Personally, my DD would just wait on that changeup if she knew it was coming in the next pitch or two. Time it up like a slow pitch on a silver platter and foul off the fastball till she got it. However, I think that can also be the difference between a skilled battery that sees a batter's weaknesses. Often times that's the coach. Sometimes, first time through the lineup, you do have to guess some. However, every swing tells you something. On a skilled batter, I think a changeup only works if they're expecting something else. HOWEVER, a pitcher that throws a changeup, then a drop curve at around the same speed with a strong FB... yeah, that pitcher can kick some a**. (Stating of course they can "locate" with acceptable skill.) Change of spin as much as speed kills 'em.