I have a bunch of small kid's trophies from when I played baseball. I was very lacking in ball holders, so I decided to do this. It is a simple modification, and it can be done in less than ten minutes.
Step 1: Remove the Nut, Disassemble Trophy
On the bottom of the trophy, there should be a nut. Undo the nut, and save it for later. Take apart the trophy, and only keep the base, the nut, the main bolt part, and any smal flat pieces of plastic that are under the actual "basebal player figure." Also keep the plastic cylinder that supported the figure.
Step 2: Remove Nameplate
Next, remove the metal plate that is engraved with your name and team. This can be done easily with a knife.
Step 3: Extra Support
You are probably going to need another part to hold the baseball or lacrosse ball onto the stand. In the two that I made, I used the top of a small plastic bottle, and the top of the box that my ipod came in.
Step 4: Done!
You now have a baseball or lacrosse ball holder. Perfect for "that special game ball" or any autographed memorobilia.
Step 5: Throw It Away?
I also came up with a use for the figures on top of the trophies; toys! Look at the picture below for more description. It is just the figure on top of a film canister.