Big doesn't only mean in height but overall body, including width and girth. Some baseball players are short but they are still quite wide and well built. Their trunks don't look especially muscular with six pack abs but they are quite girthy and have a lot of muscle packed there even if it's not contoured like a gym body. This uke's body is so twinkified, let alone a player, he doesn't even look like an adult, which is the point of the post.

They are supposed to be in their late 20s, but the uke looks ten, both his face and body. It's not a secret the author made him small because he is the uke, the typical infantilized and feminised body type, even though he is supposed to be a baseball player. It's one thing to be short, but uke's body has no musculature to speak of. Has the artist ever seen baseball players? His body also looks like a kid's. Tch.