Missing Inside To Right-Handers

My son is a 10 yr old rhp, when he struggles he misses up and inside or hits right handed batters. He never misses outside to a righty. I think he isn’t finishing/following through or his arm isn’t catching up with his body during his delivery. Has anyone been through this? Any advice will be greatly appreciated.

I do the exact same thing. It tends to be when I’m not sufficiently warmed up but after a while it usually goes away. Just try working on warming up more.

Instead of the arm being late, his front side is opening up early. This is usually case by posture issues or glove issues. Look for his head and/or upper spine pulling or leaning to the glove side. Also, look for his glove dropping, flyiing open, pulling or turning over before front foot plant.