Any time I need certain scale figures... I tend to search the WhizKids HeroClix / HorrorClix products first. These figures are almost dead-on 1/48 scale. The male figures tend to range from 1-3/8" to 1-1/2" tall, and the female figures typically range from 1-1/4" to 1-3/8" tall.
In this case, you might want to take a look at their SportsClix line. They have a full series of MLB figures that can be purchased in starter sets and individual booster packs. If you are looking for a specific pose, you can find them on the auction site for a buck or so each, or you can find them at gaming shops. I don't know the height of these figures, but I can't imagine that they would be any different than the rest of their product lines.
Here's a photo of the MLB Starter set:
HTH!
