Frame And Projectability
Before starting doing a player’s evaluation, it is always important to first look at the player's height, weight, frame, athleticism, and projectability. Listed height and weight on sites such as MiLB.com can often be misleading, especially for Dominican prospects, where it is common to see a player who weighs heavier than what is listed.
Any frame is acceptable as long as they move well for their size and shape. However, super tall players, especially pitchers, are worrying. Pitchers that are usually above 6'7" typically struggle with body control on the mound unless they are great athletes and it shows up in their mechanics. A pitcher like Sean Hjelle is a great example. He is 6'11.5" but he is an excellent athlete with the body control of a player that is more than half a foot shorter than him. Also, his mechanics is not a slow, deliberate motion but a smooth, dynamic, and rhythmic motion that results in an above-average command.
Projectability is the next aspect to look for after checking for height and weight. Projectability is predicting how a player's body frame will grow with age. It can be a bit difficult to predict, as genetics play a part in it. However, how to predict projectability if a prospect's family background is not entirely known?
Think of a player's frame as a trapezoid flipped upside down. You can google for trapezoid but simply cut a triangle horizontally then take the lower half. That is a trapezoid. Now flip that horizontally. There are only two things to look for: the broadness of the shoulders and the size of the hips. In an inverted trapezoid, are the two bases or the two straight lines at the top and bottom.
A broad shoulder is often a great start. However, in my opinion, the hips are more important in terms of projection than the shoulders because the hips will determine how much weight, hopefully, muscle, a player can tuck in the thighs and waist. A big hip usually means a big thigh bone. If a player has broad shoulders but has a small hip, the chances are the player will not gain a lot of weight. The prospect will gain weight, but only around the chest area. If a prospect is still a thin athlete but has a big hip, the player will gain weight as the player gets older because there is plenty of real estate to keep that weight gain.
Ideally, what to look out for is someone with just a moderately sized hip. That way, the prospect can gain weight but not gain too much and the prospect will have plenty of fat in his body if he overeats. A prospect with a smaller hip can still gain plenty of fat if the prospect overeats, but the chances are the prospect will not carry that weight well throughout his/her body.
The best way to see the athleticism of a baseball player is to see them on the field playing defense. If a prospect can make it look easy on defense, that is a sign of a great athlete. If you want the pure athletic metrics, though, it is best to look at their test times when they were still high schoolers attending showcases.